11Oct 2019 Think Twice about Catalina Install

[Huntn]

13Oct19 Update: My issue has been resolved, see this post for a summary: https://forums.macrumors.com/thread...-about-catalina-install.2205246/post-27871119

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First Clue I had a problem today was when Time Machine stopped backing Up with this message: Two of the disks to back up have the same name. Rename one of the disks named “Macintosh HD - Data”.

I'm on hold with Apple Tech Support trying to figure out what happened on my Catalina Install. I'm showing two hard Drives in my Finder Macintosh HD and Macintosh HD- Data. I don't think this is supposed to happen. I'll post more after a resolution is determined.
See this thread for some background: https://forums.macrumors.com/threads/catalina-install-can-it-take-all-day.2205037/
Hardware listed in my signature.

Upate1: I’ve got a senior advisor on the line which says this issue is new, it seems like a glitch, I should not see two hard drives, if I understand it correctly. Right now reinstalling Catalina OS.

 

[FNH15]

First Clue I had a problem today was when Time Machine stopped backing Up with this message: Two of the disks to back up have the same name. Rename one of the disks named “Macintosh HD - Data”.

I'm on hold with Apple Tech Support trying to figure out what happened on my Catalina Install. I'm showing two hard Drives in my Finder Macintosh HD and Macintosh HD- Data. I don't think this is supposed to happen. I'll post more after a resolution is determined.
See this thread for some background: https://forums.macrumors.com/threads/catalina-install-can-it-take-all-day.2205037/
Hardware listed in my signature.

Upate1: I’ve got a senior advisor on the line which says this issue is new, it seems like a glitch, I should not see two hard drives, if I understand it correctly. Right now reinstalling Catalina OS.

You totally should see 2 hard drives - this is a new feature in 10.15 wherein the OS resides on the partition “Macintosh HD” and your data resides on “Macintosh HD - Data”. You’ll only see one disk in Finder, but should see both in Disk Utility. I can’t speak to the Time Machine problems, though, since I myself haven’t had any issues with my Time Machine backups.

 

[Huntn]

You totally should see 2 hard drives - this is a new feature in 10.15 wherein the OS resides on the partition “Macintosh HD” and your data resides on “Macintosh HD - Data”. You’ll only see one disk in Finder, but should see both in Disk Utility. I can’t speak to the Time Machine problems, though, since I myself haven’t had any issues with my Time Machine backups.

Brought over from another thread:

Your internal HD is split into 2 partitions with Catalina.

Macintosh HD (holds OS only)
Macintosh HD- Data (holds all your program/data files)

These show up in the Finder as two hard drives.
Should they show the identical stats, same capacity, same used space? See screen shot posted. When I dig down through them, they show the same content.


Here is the (confusing) thing, I've got a senior Apple tech advisor helping me and she said, I should not be seeing two hard drives in the Finder. We also went to Disk Utility to specially check that there were not two partitions. I guess it's possible she is not up to speed or confused, but that would be kind of upsetting since Catalina is the big new thing at Apple.

I just got done with a reinstall under her supervision, and I'm back at the same spot, these two drives appear, Macintosh HD and Macintosh HD-Data, and Time Machine fails trying to back up with the message I posted earlier:

Two of the disks to back up have the same name. Rename one of the disks named “Macintosh HD - Data”.

So that message appears even though one of those drives is already named "Macintosh HD-Data".

In addition the folder contents of these two drives looks very similar if not identical with the same capacity and the same used space. When I dig down through these folders, they both show the same items:

​

I'm scheduled to talk with her again tomorrow morning. She is calling this some kind of a glitch which they are not familiar with. I said this somewhere, but if they (tech support) can't figure it out what's going on, it's going to Apple Engineers with screen shots. I suppose it might be an issue with Time Machine and not a general Catalina issue. The good news is that even though Time Machine is not working in Catalina, it does work during the Catalina setup and allows me to restore my data from MBP.

My status is that my computer is functional, but Time Machine does not work. If things don't go well tomorrow, I may suggest reverting back to Mojave if that is possible.

 

[adrianlondon]

Not sure if it helps, but here are the two containers as shown in Disk Utility. Only the main one shows in Finder (although clicking "show in Finder" in Disk Utility on the data one correctly takes me to the mountpoint) and Time Machine works perfectly.

 

[Huntn]

Not sure if it helps, but here are the two containers as shown in Disk Utility. Only the main one shows in Finder (although clicking "show in Finder" in Disk Utility on the data one correctly takes me to the mountpoint) and Time Machine works perfectly.

View attachment 868784 View attachment 868785

This is what I see on my 2016 MBP after the Catalina Intall:

Someone want to interpret? Thanks.
​

I told the rep, we should have just let Catalina install, and not selected Time Machine Restore to see what we got at that point. I wonder if there could be an issue with a Time Machine Restore, with a save from before Catalina, could be screwing with Catalina?

 

[FNH15]

This is what I see on my 2016 MBP after the Catalina Intall:

View attachment 868788
Someone want to interpret? Thanks.
​

I told the rep, we should have just let Catalina install, and not selected Time Machine Restore to see what we got at that point. I wonder if there could be an issue with a Time Machine Restore, with a save from before Catalina, could be screwing with Catalina?

Now that is interesting. My container topology does not look like that at all (I’ve been running Catalina as a clean install since the first beta) Here’s what mine looks like:

It almost looks like your data containers were duplicated by the Time Machine restore...

 

[adrianlondon]

This is what I see on my 2016 MBP after the Catalina Intall:

Unless your Disk Utility has developed a stutter then yeah, yours is messed up. I think the Catalina install takes the existing disk, which is mounted at root, and splits off the /System/Volumes/Data into a separate container. Maybe your Time Machine already had those two containers but the install was too stupid to realise and did the split again. You shouldn't have so many identically-named containers. You shouldn't have any identically-named containers

If it were me, I'd boot into recovery, totally zap your internal SSD, and then do a completely clean install of Catalina after which I'd manually restore the stuff I needed from time machine after it'd booted up.

 

[Huntn]

Unless your Disk Utility has developed a stutter then yeah, yours is messed up. I think the Catalina install takes the existing disk, which is mounted at root, and splits off the /System/Volumes/Data into a separate container. Maybe your Time Machine already had those two containers but the install was too stupid to realise and did the split again. You shouldn't have so many identically-named containers. You shouldn't have any identically-named containers

If it were me, I'd boot into recovery, totally zap your internal SSD, and then do a completely clean install of Catalina after which I'd manually restore the stuff I needed from time machine after it'd booted up.

One thing the tech person wanted to look at was to see before we started a reinstall was if Time Machine or the Catalina Installer (I’m not sure which) had created two partitions, which would have been bad as I understand it. I really don’t understand the structure of Catalina other that part of it is set aside as read only to prevent future corruption. When we looked, there re was a single partition which was good. These containers are not partitions are they, but function like locked read only folders?

Anyway, she is supposed to call back this morning to continue. A clean install of Catalina would be simplest, but the would require a huge amount of work on my part to reconstruct all of the apps I use, I’ve never tried to use Time Machine for this purpose, except a wholesale transition, transfer to a new Mac.

Now after I’m upgraded, if I still have access to Time Machine, can I go into it and pluck out individual programs to install? Or can I’m pull up something like the App Folder, and batch restore several programs at once which would include their licensees (registrations) and settings?

 

[Huntn]

One thing I’m not clear about my impression is that TM can be used to restore your computer completely including the OS or to just transfer apps and data when you transition to a new Mac which might have a newer OS in it? If accurate, in this case I want to upgrade to a new OS and just move over the data and apps, registrations and settings, but maybe TM is screwing it up.

 

[IowaLynn]

Bombich CCC blog post about APFS explains clusters and how they are treated and crested.

Working with APFS Volume Groups | Bombich Software

bombich.com

 

[Huntn]

I’ve got better things to do sit in front my Mac for several days begging Catalina to work. ? The Apple Senior tech advisor did not call me back this morning, so I am reverting back to Mojave With Time Machine. ? I called Apple to make sure I was selecting the right target drive to restore (Macintosh HD vs 3 Macintosh HD- Data(s)).

So Plan B- Start with Commnd-R selected, selected restore from Time Machine with destination disk Macintosh HD. Three hours to go, fingers crossed. ☠ ?

Of note- this mornings Apple tech person said my experience with the Catalina install is an emerging issue, other people are experiencing this and they don't yet know what triggers it.

 

[adrianlondon]

No don't do that. Delete the containers. Totally trash your internal disk config and then do the complete restore.

That's what I'd do, anyway. Your way may well work. Let us know in 3 hours

 

[Huntn]

No don't do that. Delete the containers. Totally trash your internal disk config and then do the complete restore.

That's what I'd do, anyway. Your way may well work. Let us know in 3 hours

That’s why I called Apple. ? I suggested to them that I should erase the hard drive before restoring, and was told not to worry about that, the first step of a Time Machine restore is to erase the hard drive, then start writing the TM save. ??
For future ref, how do you delete containers and trash your internal disk comfig?

 

[Huntn]

Update- The restore from Time Machine failed. ☠
Plan C- in Disk Utility I deleted the 3 Macintosh- Data volumes, I erased the Macintosh HD and am installing Catalina again, 15 minutes to go.

When it reaches a point where it asks me if I want to restore TM data, I’m going to say no, go through the Catalina setup, then check the volume structure to see if it looks like it should, see images in post 4 or 6, not like in 5.

Here is my question: After that, if I still have a good TM backup, can I restore any data (Apps ARF their settings) from it? As I mentioned before, I keep my important data on external mirrored drives separate from TM, but it would be really nice if I did not have to reinstall the 90+ apps I use, including getting them registered again.

The flip side is that it might just be good to start with a fresh MacOS and install what I need. I already saw one issue in the first version of Catalina I had installed where a program wanted me to activate, and told me I had already used my activation as if this was an additional computer I was trying to fun the program on.

3 min to go... ??
22 min to go...

 

[adrianlondon]

That’s why I called Apple. ? I suggested to them that I should erase the hard drive before restoring, and was told not to worry about that, the first step of a Time Machine restore is to erase the hard drive, then start writing the TM save. ??

Maybe, or maybe it just empties the container you pointed it to whilst leaving the container config alone. SO then you'll end up with two identically-named containers when you next attempt the upgrade.

I was assuming your backup was made from Mojave, so you'd reinstall that and all your data/apps from the TM backup. It seems you're installing the OS and then doing a TM restore. I've only done a restore once and I'm sure I didn't restore the OS separately, just restored everything from the TM backup, but I may be remembering wrong.

For future ref, how do you delete containers and trash your internal disk comfig?

No real idea - never done it, but I'm sure there's an option in recovery to run disk utility - you then just click on everything and look for delete options

 

[Huntn]

Maybe, or maybe it just empties the container you pointed it to whilst leaving the container config alone. SO then you'll end up with two identically-named containers when you next attempt the upgrade.

I was assuming your backup was made from Mojave, so you'd reinstall that and all your data/apps from the TM backup. It seems you're installing the OS and then doing a TM restore. I've only done a restore once and I'm sure I didn't restore the OS separately, just restored everything from the TM backup, but I may be remembering wrong.

No real idea - never done it, but I'm sure there's an option in recovery to run disk utility - you then just click on everything and look for delete options

Thanks for your advice. Hence my question in post 14 about recovering TM data, if you care to field that. I’m going to make sure I have a good Catalina install and then if it as option to restoreTM data ponder if this can be done from a 10.14 TM backup without screwing up Catalina.

At the end of this cycle, if Catalina is still screwed up before introducing the TM backup, I’ll go online and get an install copy of Mohave, install that and then see if my TM backup is viable to restore what I had before this fiasco.

 

[adrianlondon]

Doesn't a complete TM restore just restore the O/S anyway? Was your TM backup done in Catalina or Mojave? if Mojave, then simply restore that over a completely zapped disk config, then upgrade again. Otherwise, again do a complete zap of the disk config then a complete TM restore of your Catalina backup.

Is that what you've done? To be honest, I got confused about what you've tried and what you haven't, or even how/when you took the backup.

As for whether you can restore apps and config ... I think that's tricky. You could try restoring the apps in /Applications and the plist files in ~/Library but I suspect the official way is to restore the apps. You could try restoring the applications and then your entire user directory I suppose.

 

[IowaLynn]

Invest in Carbon Copy Cloner before beginning is great insurance. Also, double check you can boot from a backup you created with CCC.

I would go out and invest in SSD disk drive so you don't touch a working backup. APFS is slow when using spindle ddrives - really need an SSD nowadays. Slow as in 4-10x slower.

 

[Huntn]

Update 2- I’ve got a ?? working copy of Catalina along with TM!?? ?
I’ll work on a full summary for tomorrow. my Catalina Volumes look like they should. Apple wants this info.

Short summary: Continued from post 14, Plan C.

• In recovery mode: After I deleted all of the -data volumes and erased the Macintosh HD in Disk Utility. I reinstalled Catalina. My plan was not to selected migrate data from Time Machine and just see what kind of Catalina install I got.
• However, I was not home when it finished installing, and when I sat down in front of my MBP, the install had finished and I was presented with a login screen.
• Ok this is strange because each time previously when the Catalina install got to the “migrate TM data” part, soon after or before, it requested that I enter a pass word for users and to put my wifi network login in. I don’t remember doing either of those on this last install. Maybe I did, and I’m confused, but it definietly went past the point where it asked me if I wanted to migrate data from TM.
• Here is the kicker, after the last install, I thought I was looking at a Clean Catalina install, but when I started to install a program that I thought was gone, it was already sitting in my Application folder with all of the other apps I thought a clean install would flush.
• SO, WTH? Maybe some ?? divine intervention.??‍♀️ Did Time Machine run and put all these apps in? I don’t know, I wasn’t here! ? Now I just have to fiddle with setting, log into apps, see if they think I’m on a new computer and insist on activation, etc, but less work than downloading them from scratch.
• I also learned a new method of restoring apps from a TM backup. You don’t have to use the TM interface, you can open the TM hard Drive directly, proceed to the desired backup date, open the Mac HD/Applications folder, and simply pluck out the apps and pull them to the new Application folder. But I did not have to do that as previously stated. ?

Invest in Carbon Copy Cloner before beginning is great insurance. Also, double check you can boot from a backup you created with CCC.

I would go out and invest in SSD disk drive so you don't touch a working backup. APFS is slow when using spindle ddrives - really need an SSD nowadays. Slow as in 4-10x slower.

Renember those external dual backup drives I mentioned? Those and my external TM hard drive will be updated in the near future.
I had CCC at some point in the past, I’ll look into that. What advantage of is this over TM, multiple backups I presume?

 

[WilliamDu]

I know how to solve this problem.
Wait.
Reading lots of boards on Catalina, I wouldn't touch this OS with a ten foot pole.

 

[Huntn]

This is a summary of the problems I had installing Catalina. The issue appears to be resolved.
HERE are the Sympoms: After a Catalina install, you have a both a Macintosh HD, and Macintosh HD -Data showing in your Finder. That is not normal. In Disk Utility you should see both of them (That is normal). See final screen shot in this post. And if Time Machine is not working with an error message: Two of the disks to back up have the same name. Rename one of the disks named “Macintosh HD - Data”, you have a bad Catalina install, with likely duplicate data folders.

Here is the KEY: At least in my case, if you have a failed Catalina Install, before you try installing it again, in Recovery Mode, go to Disk Utility and delete all of the Macintosh HD- Data folders that appear there. Use the minus (-) button.

Catalina Marathon
by Huntn, average Mac user
sent to Apple Support 13Oct19​

This is the narrative of my experience installing Catalina, upgrading from Mojave. Prior to upgrading I took no prepatory actions, saw an update that said MacOS update and punched the button.



Part 1 First Install Attempt:

I started on Thursday (10Oct19) at about 11am and on the black and white install screen, white apple, white progress bar, I saw a lot of activity. After about 4 hours, at one point it said 9 min left, the progress bar seemed to have stalled at about an 1/4 of an inch from being complete. I looked online and saw a comment that this update can take a LONG time, and if needed, let it run all night. I was willing to do that, but decided to call AppleCare support.

The update stalled. It’s possible that I did not have enough disk space, but the installer did not warn me of that at any point.

Part 2 Second Install Attempt:
Called Applecare. With an Apple Tech on the phone:

• After stalling with the progress bar almost full, I restarted my MBP holding start button. It restarted to the same black and white screen, white Apple and white progress bar, at the same point of progress..
• Restart holding Shift- same result.
• Restart holding Shift R or Command R (one of them) got me to the Recovery screen.
• Chose Install MacOS- and it indicated I was 17Gb short of space. Hit Esc.
• Chose Disk Utility at this point there was a Macintosh HD and Macintosh HD-Data and chose Macintosh HD and erased.
• Closed Disk Utility, back to options screen to install MacOS Catalina, it completed it’s install and I thought I was home free.
• Afterwards, I was supposed to get a case number via my email, but that never arrived.

However, I soon noticed that Time Machine was not working, I clicked on the error message and “i” and read this message:

Two of the disks to back up have the same name. Rename one of the disks named “Macintosh HD - Data”.

On my finder I could see both of these volumes but one was labeled Macintosh HD and the other Macintosh HD- Data. So that message appeared even though one of those drives is already named "Macintosh HD-Data". Reminder: you are not supposed to see both of these in your Finder/Desktop.

I noticed that when I pulled up Time Machine, it looked like there are a bunch of pages, but I can’t access them, like you normally can.

About Macintosh HD and Macintosh HD- Data that appear in my finder- these showed up in the Finder as two hard drives. They showed identical stats, same capacity, same used space. And when I dug down through them, they show the same content.

Part 3 Third Install Attempt:
The next day I called Applecare support and got assigned to XX, a senior advisor. With her on the phone and doing some screen sharing.

• She said, I should not be seeing two hard drives in the Finder.
• We went to Disk Utility to specifically check that there were not two partitions.
• At this point there were two Macintosh HD- Data volumes showing.
• So we went through the same install process, launch into recovery mode, Install OS Catalina it installed.
• During new OS setup was asked if I wanted to install data from another source. I said yes, and chose my Time Machine backup restoring my data and apps.
• The install finished, but I found I was at the exact same point as before, Time Machine not working and when Disk Utility was pulled up, now there were 3 Macinstosh HD- Data volumes, and I still had Macinstosh HD and Macinstosh HD- Data showing in the finder.

Part 4 Forth Install Attempt:
Senior Apple Advisor was supposed to call me back on Saturday morning at 10am, but was either with another customer or got sick, not sure. I later got a call from her assistant telling me she was not feeling well. I did get a case number.

So I’ve decided enough of this, i’m just going to revert to Mojave using Time Machine, but a I decided to call Apple Support again and spoke with Memi. I told her I just wanted to revert back to Mojave and remembering we had erased a hard drive on a previous install attempt, I asked her if I should be erasing any of these 4 volumes I was looking at beforehand? She told me that doing a Time Machine backup should write over the disk, so with her help

• Pulled up Recovery screen and selected Restore from Time Machine backup.
• About 3 hours later a message popped up Time Machine restore failed (or something like that).

Part 5 Fifth Install Attempt:
BTW, everyone I talked to was friendly and helpful, wanted to help so this story is not intended to get anyone into trouble. So now I’m really frustrated and decide to go for the nuclear option all by myself.

• In recovery mode, I open Disk Utility and gleefully delete all three Macinstosh HD- Data volumes and I erase Macinstosh HD. I’m going for a clean Catalina Install, thinking Time Machine is the enemy.
• I do have a family life even through I am retired, so we leave the house for a nice 2 hour drive through the country and when I get back I’m expecting to see a screen saying do I want to migrate data from anther source (like Time Machine)?
• But instead I see a Catalina Log in screen.

I log into Catalina, to find that Time Machine is working, and when I open up Disk Utility I see:

Which looks to me to be a normal Catalina Install ? and I’m thinking I’ve got a Clean Install on my hands and I’m going to go have to download and reconstruct all of those 90+ apps I use on my Mac.

A helpful Apple Senior Advisor named Jerome, advised me that I could easily go pull up the Time Machine Volume, find the Apps folder from an older backup and simply drag my old apps from there over to my new Application folder. But when I went to do this to my surprise, all of my old apps were sitting in the new Catalina Application folder! ?‍♀️

I’m a bit confused because I was not there like the previous 4 install attempts to tell it to restore data from Time Machine, but this time it must have defaulted to that setting and I surmise that the reason I got a good Time Machine backup is because I had manually deleted all of those Macinstosh HD- Data volumes before starting this install attempt. Am I smart or just lucky?

So I don’t think Time Machine is the culprit. I do think that with Catalina, in the event of a failed install, before trying again, you MUST delete all of the Macinstosh HD- Data volumes you might see in Disk Utility or you are not going to get a good Catalina install as it will create a new data volume in addition to the original.

Btw, I keep all of my important data on duel external hard drives separate from Time Machine that are kept mirrored with a sync program and are also backed up to the cloud, so I was not sweating losing data. I was sweating putting my MBP back together though, and it looks look I dodged that bullet.

I think Apple needs to do a better job of explaining why I can’t just plunk down a folder anywhere in the Macintosh HD like I used to, and that I have to go to some place like Documents to add a folder. Did they and I missed it?

I want to thank all of the Apple tech support people who got involved to help. I realize that this is a new Operating System and there are new thing that might pop up. I hope this narrative helpful to Apple Care advisors and Apple Engineers.

 

[WilliamDu]

Just think about all the time saved, apple support guys in particular, if Apple had withheld this thing until they had all the bugs eliminated.

 

[0906742]

I'm just downloading Catalina to update my Mojave. Not sure updating it over Mojave was a good idea but I'll give it a try, as this is obviously the suggested route from Apple and I'm feeling quite lazy trying to avoid starting over again from clean. I also have basically installed just 2-3 apps so I don't except update install should carry much garbage from old installation.

Anyway my first download from automatic software update was cut for some reason about half way thru, it said something like connection was lost so I just restarted it and to my surprise it did not just continue from where it was left but started counting up from 0. Again, no problem but when I look at free disk space I can see that it did not automatically release that 4-5GB it had already downloaded and it is decreasing the disk space as second attempt to download it is running.

So my question is how to free disk space and delete that cancelled update 4-5GB data it left on the disk? Where it is? Or does it delete it when update is installing?

 

[Huntn]

I'm just downloading Catalina to update my Mojave. Not sure updating it over Mojave was a good idea but I'll give it a try, as this is obviously the suggested route from Apple and I'm feeling quite lazy trying to avoid starting over again from clean. I also have basically installed just 2-3 apps so I don't except update install should carry much garbage from old installation.

Anyway my first download from automatic software update was cut for some reason about half way thru, it said something like connection was lost so I just restarted it and to my surprise it did not just continue from where it was left but started counting up from 0. Again, no problem but when I look at free disk space I can see that it did not automatically release that 4-5GB it had already downloaded and it is decreasing the disk space as second attempt to download it is running.

So my question is how to free disk space and delete that cancelled update 4-5GB data it left on the disk? Where it is? Or does it delete it when update is installing?

Gosh, ideally the installer would ideally detect the results of it’s previous attempt. In Steam I deal with partial installer downloads frequently, and there they just pick up where they left off, but the difference is they are not creating volumes.

I am fairly confident that the issues I had with my Catalina Install boiled down to one issue, when the Catalina Installer failed on the first attempt (don’t know why) on the second attempt it created a duplicate Macintosh HD-data volume (and on each subsequent attempt) which dooms the install to failure.

My impression is that before your try a second Catalina install you must look at Disk Utility and see if the Macintosh HD-data volume already exists. If it exists with the Catalina Installer as it currently exists, an additional Macintosh HD-data volume will be created during the install, boogering it. In hindsight, it is easy to fix as I mentioned in post 21.:

Prior to a second Catalina install attempt, launch in recovery mode (on Start, hold Shift R) and selecting Disk Utility, delete any Macintosh HD-data volume that currently exists, close Disk Utility and then proceed with the Catalina Install. When I was faced with this, I also erased the Macintosh HD volume, even though the installer is supposed to erase the volume. Now you probably know if you don’t have a TM backup, at that point you are committed at that point.

I’m surprised that Apple did not know this was a possibility, but apparently it’s not a scenario they anticipated. None of the Apple Advisors or the Senior Advisor I worked with knew of this except they should know now. I imagine at some point the Catalina installer will be fixed so that it checks before it creates a new and duplicate Macintosh HD-data volume.

 

[0906742]

My impression is that before your try a second Catalina install you must look at Disk Utility and see if the Macintosh HD-data volume already exists. If it exists with the Catalina Installer as it currently exists, an additional Macintosh HD-data volume will be created during the install, boogering it. In hindsight, it is easy to fix as I mentioned in post 21.:

Just to clarify situation this happened during downloading the update, not while it was installing. So it for some reason cut connections or something and download was cancelled but when I started it again it begin to download it from 0 and I could see hard drive space was still reserved by the failed one (about 4-5GB).

Anyway, second download was successful and it installed OK but I guess there is still a lot of garbage left as it shows there is about 20GB space possible to free in Disk Utility. Also I see in Disk Utility that there are just two "partitions" Macintosh HD and Macintosh HD - Data.
However as I'm newbie in MacOS and I've only used Mojave before this I was wondering how to actually access to Data? It automatically created desktop shortcut to Macintosh HD, but not to Macintosh HD - Data, so I'm unable to create new folder to root of that Macintosh HD like before? How to do that?
Also it created relocated items folder. Can I just delete it? There are only few files I recognize and I'll move them to HDD when I figure out how to create new folders there?

I guess I could try command that free disk space TM reserves for backups? Would this command work in Catalina too "tmutil listlocalsnapshotdates / |grep 20|while read f; do tmutil deletelocalsnapshots $f; done" ?

EDIT:
Yeah, that tmutil... command took care of that 20GB garbage. Now I have even more disk space than I had with Mojave. I was worried how well 128GB SSD would suffice with new OS but seems no problem.

Also I understand now more about that creating folders in root, it is not recommended anyway and it is prevented by default in Catalina. So I just move the stuff I wanted to save from Relocated Items folder to user folder and deleted the rest, so no Relocated Items folder anymore on desktop.