You should go back in time and use the TM backup from the old install. Newer backups may carry over the permissions issues.
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It will be missing anything you added in the last week. But after the migration you can still go into the newer TM backup and manually restore for example a document you created in the last week.
You might be able to continue with the old TM from the old install, but not the newer TM. TM has limited capability across different versions, particularly going backwards.
Once you get everything restored, you should be able to reconfigure the same Arq backup set and keep on going.
With my new Mac, continued the good backup practices I gratefully learned in this thread years ago:
Have been saved by it a few times, and they were enough to keep me convinced.
- Stuck with good ol’ 3-2-1 backup.
- Still using Arq for online backups. Now using both Arq Cloud Storage and Backblaze B2 (so, 4-2-1?).
- Still using Carbon Copy Cloner and Time Machine for local backup to two separate external drives.
Have been saved by it a few times, and they were enough to keep me convinced.
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“Macintosh HD”, “Macintosh HD - data” and Time Machine questions.
I am not a computer person so forgive me asking experts elementary questions. I had spent a lot of time searching the internet for answers, but after much effort am still confused.
I understand that for the latest versions of Mac OS that use APFS, the internal hard disk of the Mac is divided in to “Macintosh HD” and “Macintosh HD - data”, the former contains system files, which could not be modified, while the later contains all the user’s data.
I also understand that Time Machine only backups “Macintosh HD - data” (yes?).
Also CCC and Chronosync offer an option to only backup the Macintosh HD - data if the user does not need an bootable backup. This option suggests that only “Macintosh HD - data” is needed for recovery, yes?
Therefore I do not need a bootable backup, if I use Mac recovery assistant, yes?
Does this mean that when I use mac’s recovery assistant to install a new mac OS followed by migration using either TM or CCC, all they need is “Macintosh HD - data,” yes ?
Does “Macintosh HD - data” includes all the applications I had installed such as MS office, yes? Or I have to reinstall them and supply the key codes?
If I want to backup my Mac to the cloud (for example Dropbox, or ARQ) , all I need is to backup “Macintosh HD - data” to the cloud, yes?
I sincerely thank you in advance for sharing your knowledge.
I am not a computer person so forgive me asking experts elementary questions. I had spent a lot of time searching the internet for answers, but after much effort am still confused.
I understand that for the latest versions of Mac OS that use APFS, the internal hard disk of the Mac is divided in to “Macintosh HD” and “Macintosh HD - data”, the former contains system files, which could not be modified, while the later contains all the user’s data.
I also understand that Time Machine only backups “Macintosh HD - data” (yes?).
Also CCC and Chronosync offer an option to only backup the Macintosh HD - data if the user does not need an bootable backup. This option suggests that only “Macintosh HD - data” is needed for recovery, yes?
Therefore I do not need a bootable backup, if I use Mac recovery assistant, yes?
Does this mean that when I use mac’s recovery assistant to install a new mac OS followed by migration using either TM or CCC, all they need is “Macintosh HD - data,” yes ?
Does “Macintosh HD - data” includes all the applications I had installed such as MS office, yes? Or I have to reinstall them and supply the key codes?
If I want to backup my Mac to the cloud (for example Dropbox, or ARQ) , all I need is to backup “Macintosh HD - data” to the cloud, yes?
I sincerely thank you in advance for sharing your knowledge.
Yes. And Finder presents them as one.
Yes
Yes
Yes. Boot to recovery (from boot disk or from Internet), erase disk, install macOS, Migration Assistant.
Yes
TM and CCC backup all apps, settings and most data (not caches, logs, etc.). Migration Assistant will recover all that. No need to reenter key codes, though for apps which require web login (Adobe, MS subscription, etc.) you may need to login which requires your passwords.
Yes, but:
Dropbox (like iCloud, OneDrive, etc.) is a synchronisation product. Arq is a backup which keeps full history of files and folders and makes recovery to a past point in time straight forward.
Cloud backup products are not well suited to Migration Assistant style recovery. Better suited to recovery of important data after a reinstall of macOS on same or new computer. There are no cloud products which create a backup suited to Migration Assistant. Arq, Backblaze, etc. will not do a full system recovery.
So you probably don't need to backup everything.
Need to consider what threats you are mitigating by using Arq and tailor your backup to enable recovery. In my case I use Arq to mitigate destruction of files and data following "serious" disaster - e.g. fire, theft, electrical destruction of computer equipment. For unlikely events I am content with recovery which will be slow and involve reinstallation of apps, etc. I am just concerned to recover data - photos ,documents, etc.
So, my Arq backup is focused on documents, photos, etc. - not the system as whole.
Questions on Time Machine backup to cloud, snapshots and CCC restore, usefulness of bootable backup
You answered my questions that I have for years in minutes. My sincere thanks! Below are more elementary questions.
Question on syncing a TM or CCC backup to the cloud
Disregards whether it is desirable or recommendable, Suppose a paranoia person just want to backup the TM or CCC external disk to the cloud, just for the peace of mind. Previous to APFS, I read that a cloud provider had done an experiment by backing up the TM drive (which were doing hourly, daily backups, etc) to the cloud and compared the size of the backup on the cloud with that on the external drive as well as comparing the rate of size increase, he found that the size of the TM backup uploaded to the cloud was several times that of on the external SSD, likewise for the rate of size increase. The obviously conclusion is that one should not backup Time Machine to the cloud because of size consideration. The article explained this size increase is due to the use of hard links.
Now TM uses APFS and does not use hard links. The size increase mentioned above may not occur. Should this be the case, Is it possible to sync (not backup) the external SSD doing TM (or CCC) backup to the cloud? On the event of catastrophe, one could download the cloud copy. Even though it may take a long time, but in theory, it could be downloaded and could work. Yes?
Question on snapshots
When the external TM disk is not plugged in, I understand that TM stores the hourly snapshots on the Macintosh HD (or Macintosh HD-data, not sure which), yes? But later when the external TM disk is plugged in, TM does its normal hourly backup, that is it does not create hourly snapshots, yes? What happens to the snapshots created previously? Nothing happens to them, yes?
Question on how to do CCC backup when backup contains snapshots
I read that CCC creates a snapshot on the destination drive before each backup. For daily backup, after one week, I will have 7 snapshots on the destination backup disk. Now the Macintosh HD fails. I use CCC to clone the CCC backup to the Macintosh. So the 7 snapshots previously on the CCC backup are also cloned to the Macintosh HD. This is OK because as far as snapshot goes, whether it is created by CCC or TM does not matter because they are the same, yes?
Question if it is useful for backup to be bootable
I also read that for Macs that have the apple silicon chip, a bootable backup is not necessary because when the Macintosh HD fails, it couldn’t be booted by an external disk. So it is better off just backup only the Macintosh HD-data because it is less complex to do and save disk space, yes?
Finally, a dump question. Using APFS, is there any fundamental reason that prevents apple to offer Time Machine backup to the cloud?
You answered my questions that I have for years in minutes. My sincere thanks! Below are more elementary questions.
Question on syncing a TM or CCC backup to the cloud
Disregards whether it is desirable or recommendable, Suppose a paranoia person just want to backup the TM or CCC external disk to the cloud, just for the peace of mind. Previous to APFS, I read that a cloud provider had done an experiment by backing up the TM drive (which were doing hourly, daily backups, etc) to the cloud and compared the size of the backup on the cloud with that on the external drive as well as comparing the rate of size increase, he found that the size of the TM backup uploaded to the cloud was several times that of on the external SSD, likewise for the rate of size increase. The obviously conclusion is that one should not backup Time Machine to the cloud because of size consideration. The article explained this size increase is due to the use of hard links.
Now TM uses APFS and does not use hard links. The size increase mentioned above may not occur. Should this be the case, Is it possible to sync (not backup) the external SSD doing TM (or CCC) backup to the cloud? On the event of catastrophe, one could download the cloud copy. Even though it may take a long time, but in theory, it could be downloaded and could work. Yes?
Question on snapshots
When the external TM disk is not plugged in, I understand that TM stores the hourly snapshots on the Macintosh HD (or Macintosh HD-data, not sure which), yes? But later when the external TM disk is plugged in, TM does its normal hourly backup, that is it does not create hourly snapshots, yes? What happens to the snapshots created previously? Nothing happens to them, yes?
Question on how to do CCC backup when backup contains snapshots
I read that CCC creates a snapshot on the destination drive before each backup. For daily backup, after one week, I will have 7 snapshots on the destination backup disk. Now the Macintosh HD fails. I use CCC to clone the CCC backup to the Macintosh. So the 7 snapshots previously on the CCC backup are also cloned to the Macintosh HD. This is OK because as far as snapshot goes, whether it is created by CCC or TM does not matter because they are the same, yes?
Question if it is useful for backup to be bootable
I also read that for Macs that have the apple silicon chip, a bootable backup is not necessary because when the Macintosh HD fails, it couldn’t be booted by an external disk. So it is better off just backup only the Macintosh HD-data because it is less complex to do and save disk space, yes?
Finally, a dump question. Using APFS, is there any fundamental reason that prevents apple to offer Time Machine backup to the cloud?
One difficulty is "what would you sync?" TM and, by default, CCC create an APFS volume and in that volume make a snapshot for each backup. So you would, presumably, sync the latest snapshot. By the time that is finished (some days/weeks later) there would be many more snapshots - would you skip them? And some deleted (thinned) from 1 per hour to 1 per day to 1 per week - would you want to delete them? It kind of gets messy to even decide what you want to do.
And would it be useful for recovery? Not, I think, for a Migration Assistant recovery. Yes, for a folder and file recovery.
But for a file and folder recovery it would have been easier to have used Arq (or Backblaze, Crashplan, etc.) which can recover particular folders, etc. without any need to restore the whole backup.
Snapshots are of the Macintosh HD-data (since that is the only varying volume). The "local" snapshots are removed after 24 hours. The new snapshots on the external TM disk, would be deleted according to TM's internal rules about thinning. Note, I have not tested this - on my MacBook I run TM manually whenever I connect the external disk. The snapshots on the external get thinned as expected to 1 per day and then 1 per week as best it can.
With CCC you can configure how it does the thinning.
By default (and unsupported) CCC does not make bootable clones. I would avoid that path. Just configure CCC to make backups (with snapshots) which are Migration Assistant compatible.
Also "cloning" (as per CCC) clones the current snapshots, not past ones. So if you cloned back from external to internal you would only get the most recent snapshot.
Much depends on your Mac hardware...
There are those who like bootable clones. I am amongst those who don't for recent Macs.
With older Intel Macs you can boot directly from an external drive and this provided fast recovery following failure of the internal disk. As you know, this is not true for an Mx Mac. The initial boot for an Mx Mac is to boot from a hidden partition on the internal disk. This then loads macOS from the Macintosh HD from either internal or (if you allow it) external. So the only value of a clone is for protection in case you make your internal macOS so corrupt it won't start - that is no protection from hardware failure.
Yes, network speed.
Time Machine without major redesign would be very network intensive.
For backup, it is bad enough when the TM destination is on a local network share - it would grind to a halt if the destination were over the internet. Backup performance could be alleviated if TM kept a local index of the TM cloud copy. Just like Arq, etc. do.
Apple could offer to synchronise the TM volume (and its snapshots) to iCloud in the background (for those with adequate connectivity). Apple would then need to provide a web based recovery tool for individual files and folders (like Backblaze) or another app (e.g. like Arq's recovery).
Full system recovery becomes problematic except to a Mac which has ~1Gb/s network throughput all the way from a Mac to Apple's servers.
Once again my sincere thanks for answering my elementary questions! Your answers have benefited me greatly. They clarified issues which are confusing to I when I do backup.
“…..Just configure CCC to make backups (with snapshots) which are Migration Assistant compatible.
Also "cloning" (as per CCC) clones the current snapshots, not past ones. So if you cloned back from external to internal you would only get the most recent snapshot.”
——- How do I configure CCC such that when use for restore a Mac, the backup contain only the most recent snapshot (do I even need this snapshot at all?) and is “Migration Assistance compatible”. Do I have to do anything special?
Also want to double check with you, going forward for both TM and CCC, I only need to backup “Macintosh HD-data” only. I do not need to back up “Macintosh HD”, yes? This backup together with “Migration Assistant” will completely restore my Mac, yes?
“…..Just configure CCC to make backups (with snapshots) which are Migration Assistant compatible.
Also "cloning" (as per CCC) clones the current snapshots, not past ones. So if you cloned back from external to internal you would only get the most recent snapshot.”
——- How do I configure CCC such that when use for restore a Mac, the backup contain only the most recent snapshot (do I even need this snapshot at all?) and is “Migration Assistance compatible”. Do I have to do anything special?
Also want to double check with you, going forward for both TM and CCC, I only need to backup “Macintosh HD-data” only. I do not need to back up “Macintosh HD”, yes? This backup together with “Migration Assistant” will completely restore my Mac, yes?
You do need to be prepared to read CCC documentation and the many hints and tips on the web site. It is more complex than TM. If you are not sure, use TM.
CCC help shows you how to ensure a Migration Assistant backup. Mostly this is the default is the source is your internal disk and the destination is an empty APFS volume on the external.
You just tell it to backup your internal disk Macintosh HD (or whatever yours is called). CCC and TM sort out what to backup.
With TM you just go ahead and set it up - possibly adding a few exclusions. With CCC you need to try different things and decide what is approbate for you - mostly defaults will work for a TM like backup.
CCC help shows you how to ensure a Migration Assistant backup. Mostly this is the default is the source is your internal disk and the destination is an empty APFS volume on the external.
You just tell it to backup your internal disk Macintosh HD (or whatever yours is called). CCC and TM sort out what to backup.
With TM you just go ahead and set it up - possibly adding a few exclusions. With CCC you need to try different things and decide what is approbate for you - mostly defaults will work for a TM like backup.
Thanks again and hope to bother you with one more dump question.
What you said should apply to ARQ (which I also use in addition to TM and CCC).
If I have to start a new backup today, I should just set it up so that it backup Macintosh HD-data. I was told by members of this forum that ARQ is not designed for full recovery of the Mac like TM and CCC, but rather is a “web based recovery tool for individual files and folders”.
But if disaster strikes and ARQ is the only backup I have, if there any reason that I could not download the ARQ backup of “Macintosh HD-data”, to be used with migration assistant? Just like TM and CCC woulds?
What you said should apply to ARQ (which I also use in addition to TM and CCC).
If I have to start a new backup today, I should just set it up so that it backup Macintosh HD-data. I was told by members of this forum that ARQ is not designed for full recovery of the Mac like TM and CCC, but rather is a “web based recovery tool for individual files and folders”.
But if disaster strikes and ARQ is the only backup I have, if there any reason that I could not download the ARQ backup of “Macintosh HD-data”, to be used with migration assistant? Just like TM and CCC woulds?
Don't get too hung up about Macintosh HD-data. Just configure the backup to backup all or part of the system disk - that is Macintosh HD.
Yes. I would put it as Arq (like other cloud backup solutions) is a "cloud based backup and recovery tool for individual files and folders". When recovering (using the Arq application) you can recover large folder trees in one go.
When you create a backup plan with Arq it offers three starting points: "Backup all drives with standard exclusions", "Backup user data on Macintosh HD, with standard exclusions", and "I will choose the folders to back up". I use the third starting point and work from there. But you should play around with the configuration to get a feel for it. If you have a spare external drive, do some test backups to that.
No. Arq backups are not structured to work with Migration Assistant. And, a TM or CCC backup which has been synchronised to a cloud service could not be got back in a state ready for Migration Assistant.
If Arq is the only backup you have (e.g. after your disks are corrupted or your house burns down), get a new Mac, install macOS, users and apps and then use Arq to recover files and folders and settings. Probably do the Arq recovery before installing most apps. Do enough tests to confident you can recover in the event of disaster.
Thank you for being generous with your time and for sharing your knowledge to answer my questions. Your suggestion of doing experiments for different scenarios and settings is a very good one. I didn’t know that ARQ can backup to an external disk, which would make doing experiments possible. (I just bought a 2TB SSD for doing what you had suggested.)
“No. Arq backups are not structured to work with Migration Assistant.”
—— This has been confusing me for years. Hypothetically, suppose I have a CCC or TM backup up on an external disk-1. I use ARQ to back up the entire external disk-1 to the cloud. After completion, I then immediately download the contents in the cloud to another external disk-2. Is external disk-1=external disk-2?
“And, a TM or CCC backup which has been synchronised to a cloud service could not be got back in a state ready for Migration Assistant.”
—— Similar question. I sync external disk-1 to the cloud, so that the cloud is a mirror copy. After one week, I download to external disk-2. Is external disk-1=external disk-2?
Question on backing up TM and CCC on the same disk
Samsung now has a 4TB SSD at a reasonable cost. If I partition the disk into two volumes, one for TM and the other for CCC. What will happen if both try to backup at the same time? Will conflict corrupt the backups? Also I understand in APFS the size of the volume is dynamic. Will it be a problem as the backups grow in size?
“No. Arq backups are not structured to work with Migration Assistant.”
—— This has been confusing me for years. Hypothetically, suppose I have a CCC or TM backup up on an external disk-1. I use ARQ to back up the entire external disk-1 to the cloud. After completion, I then immediately download the contents in the cloud to another external disk-2. Is external disk-1=external disk-2?
“And, a TM or CCC backup which has been synchronised to a cloud service could not be got back in a state ready for Migration Assistant.”
—— Similar question. I sync external disk-1 to the cloud, so that the cloud is a mirror copy. After one week, I download to external disk-2. Is external disk-1=external disk-2?
Question on backing up TM and CCC on the same disk
Samsung now has a 4TB SSD at a reasonable cost. If I partition the disk into two volumes, one for TM and the other for CCC. What will happen if both try to backup at the same time? Will conflict corrupt the backups? Also I understand in APFS the size of the volume is dynamic. Will it be a problem as the backups grow in size?
Cloud backup products like Arq backup files and folders. They do not backup the APFS volume with its structure of snapshots, etc. In addition TM volumes are an APFS type can only be created by TM.
No. It is not a mirror copy of the APFS volume - it is a copy of the files and folders of a particular snapshot (and ignoring file system structures such as hard links) - not quite the same thing.
Create one APFS partition/container for the whole disk and create two volumes inside. Yes, they will grow dynamically. The only problem with size is that you need to keep an eye on the total size to make sure the whole container does not get too full.
Thanks again! Would appreciate assistance in upgrading MAC OS.
I have Mojave and would like to upgrade to a more recent OS such as Big Sur (or Sonoma). I understand that the former is 32 bit whereas the latter is 64 bit. Thus most if all of my applications will not run under the new OS. I intend to have a clean install and upgrade all my apps to 64 bit. For the past years when upgrading to newer Mac OS, I always used Time Machine and Migration Assistant to transfer all the user information as well as apps and I never had to do a clean install. That has worked out well for me because clean install was a bit beyond my technical ability.
Now I am forced to do a clean install. After much research, it seems that I should just use the disk utilities to erase the Macintosh HD, then install the new OS, fill in information in setup, and at this point, the Mac is fully setup to run. Next, I will use CCC backup to copy over the following user specific folders: Desktop, Document, Picture, Music, Movies and Download. And finally install new apps. I really do not need to use Migration Assistant, which may migrate data that violate clean install. Am I correct?
I have Mojave and would like to upgrade to a more recent OS such as Big Sur (or Sonoma). I understand that the former is 32 bit whereas the latter is 64 bit. Thus most if all of my applications will not run under the new OS. I intend to have a clean install and upgrade all my apps to 64 bit. For the past years when upgrading to newer Mac OS, I always used Time Machine and Migration Assistant to transfer all the user information as well as apps and I never had to do a clean install. That has worked out well for me because clean install was a bit beyond my technical ability.
Now I am forced to do a clean install. After much research, it seems that I should just use the disk utilities to erase the Macintosh HD, then install the new OS, fill in information in setup, and at this point, the Mac is fully setup to run. Next, I will use CCC backup to copy over the following user specific folders: Desktop, Document, Picture, Music, Movies and Download. And finally install new apps. I really do not need to use Migration Assistant, which may migrate data that violate clean install. Am I correct?
Unable to understand experimental results. Hope someone could help explain what has happened or what stupid experiments that I have done. The hypothetic scenario is all land backups are destroyed, but I do backup to the cloud.
I understand that for Mac the internal disk now divided into Macintosh HD and Macintosh HD-Data. The former contains read only system files and system preinstalled apps, whereas the latter contains all the user data including user installed apps. Because the Macintosh HD is no longer accessible, CCC now only backs up Macintosh HD-Data and does not offer (or discourage the use of) a bootable backup. To restore, both CCC and Time Machine must use Migration Assistant (MA) which requires a working OS.
I was told that folders downloaded from the cloud wold not work with MA. This has consequence as it would mean that if I download all the relevant folders in Macintosh HD-Data from the cloud, for example from ARQ, I would be able to use them with MA. I have backups from both CCC and TM and proceed to do the following experiments.
1) I created a new APFS partition on an external drive and copied all folders from either the CCC or TM backup to this partition. I use this partition with MA. It indeed does not work. MA reports that the partition contains a damaged Mac OS and goes no further.
2) To imitate downloading folders from the cloud, I deleted all the folders in the CCC backup and replace them with those in the TM backup. I use this modified CCC backup with MA. This approach works and the Mac is restored by this modified backup. I have done this on two different days and the results are the same that is both time using the modified CCC backup, MA work and the Mac is restored.
3) I try to do the same thing to the TM backup, but found that TM would not allow me to delete any of its folder.
Does the result of (2) means that I could use CCC backup as a shell then replaced its folders with those downloaded from the cloud such as ARQ and this surrogated CCC backup will work with MA?
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