APFS partition error

[KRVE]

Hi all,

Recently one of my Macs (High Sierra) died and when I wanted to erase the drive to give it another purpose I found out that APFS drives are not read when connected externally. As a next step I've put the drive inside another Mac (Catalina + has a secondary drive) and when I entered recovery Disk Utility it showed errors on the disks.

I've tried to let Disk Utility fix the issue but my Mac freezed on "Discovered new Logical Volume Group" and I had no choice but to turn it off after hours of no progress. When I turned on my Mac again the secondary drive became unreadable as well and I'm unable to fix the volume with first aid (also not in recovery or with terminal). I have a partial backup of the secondary drive but there is some important work in progress on it from last week that I unfortunately forgot to backup.

Different data recovery apps are showing the contents of the disk but the recovery process takes a while and I was wondering if there is a way to just recover the partition instead.

Thanks,

Milan

 

[chabig]

Probably not. It sounds like it's failed (APFS drives should work normally even when external) and should just be replaced. I'm sorry about the work you may have lost, but at least it was only a week's worth.

I know it's not the time to lecture, but Apple makes two products that would have saved your data; 1) Time Machine would have limited your data loss to just the last hour, and 2) iCloud documents would also protect from local drive failure (as well as theft, fire, flood, earthquake...).

 

[DeltaMac]

The beginning of your post, you said you wanted to erase the drive.
Is that still your goal?
Don't worry about repairing a bad partition. Just erase the drive. Choose the device (change the View menu to Show All Devices), and then erase. That will work without even knowing if the partition has an error of some kind.

 

[honestone33]

The beginning of your post, you said you wanted to erase the drive.
Is that still your goal?
Don't worry about repairing a bad partition. Just erase the drive. Choose the device (change the View menu to Show All Devices), and then erase. That will work without even knowing if the partition has an error of some kind.

Yes, just start up Disk Utility, select the very top name of the drive, and select Erase and Format. You should select for the Format, Mac OS Extended (Journaled), and for the scheme, GUID Partition Map.

Also, regarding the OP's original statement, "I found out that APFS drives are not read when connected externally", that is not true. I have a Samsung 850 Pro 512 gig SSD inside an Orico Enclosure, and it has 3 APFS partitions. Two of them are for my SuperDuper! backups for each of my Catalina-based Macs, and the other one contains Miscellaneous folders, files, etc. (quite a few movies and TV Series). Any of those partitions can be read by either of my Macs.

Now, if I was using an OS prior to High Sierra, then what the OP said is accurate.

Also, I recently purchased a Samsung 1 TB T7 external SSD. I plan on partitioning it into 3 partitions: one will be for testing Big Sur, one will be for movies, and the other will be for TV Series. I will want to use the SSD with either of my Roku Ultra Streaming devices, and each of them has a USB port (I can connect that Samsung T7 to either a Thunderbolt port, or a USB port, as it came with 2 such cables). For me to be able to view either a movies, or a TV series, via that device, it will be necessary to format those 2 partitions as Mac OS Extended (Journaled), and GUID Partition Map. Even if I initially format the Big Sur partition as Mac OS Extended, when I install Big Sur on it, that partition will be formatted (by Big Sur) as APFS.

 

[chabig]

Also, I recently purchased a Samsung 1 TB T7 external SSD. I plan on partitioning it into 3 partitions: one will be for testing Big Sur, one will be for movies, and the other will be for TV Series. I will want to use the SSD with either of my Roku Ultra Streaming devices, and each of them has a USB port (I can connect that Samsung T7 to either a Thunderbolt port, or a USB port, as it came with 2 such cables). For me to be able to view either a movies, or a TV series, in that device, it will be necessary to format those 2 partitions as Mac OS Extended (Journaled), and GUID Partition Map. Even if I initially format the Big Sur partition as Mac OS Extended, when I install Big Sur on it, that partition will be formatted (by Big Sur) as APFS.

Two things:

1. The Samsung T7 is a USB drive. It comes with two USB cables, one Type A and one Type C. It's not quite correct to call USB C a Thunderbolt port because many USB C ports don't support Thunderbolt.

2. I didn't know that Roku's could read HFS+. That is nice to know!

 

[honestone33]

Two things:

1. The Samsung T7 is a USB drive. It comes with two USB cables, one Type A and one Type C. It's not quite correct to call USB C a Thunderbolt port because many USB C ports don't support Thunderbolt.

2. I didn't know that Roku's could read HFS+. That is nice to know!

Hmm, I can connect that T7 to any of the 4 Thunderbolt 3 ports on my Mac Mini, via the supplied cable. And the quoted speed, via that cable, is, according to this, "Reads up to 1,050 MB/s / Writes up to 1,000 MB/s on USB 3.2 gen 2 supported devices*". And the "*" means:

• *SAMSUNG RECOMMENDS users to download the latest firmware update via the included Portable SSD Software 1.0 to ensure optimal performance

It looks like my late 2018 Mac Mini does not have USB 3.2 gen 2. The System Report says via the USB 3.1 bus, when I have that T7 connected to one of the Thunderbolt 3 (USB-C connector) ports. So, I thus assume I will not get those speeds?

 

[honestone33]

OK, I guess i can use some help here. I was reading this:

Compared: USB 3, USB 4, Thunderbolt 3, Thunderbolt 4, USB-C - what you need to know | AppleInsider

With the varieties of USB and Thunderbolt terminology floating about, as well as new versions being adopted by Apple and other device producers, sorting out the mess can be a problem. Here's what you need to know about USB 3, USB 4, Thunderbolt 3, and Thunderbolt 4.

appleinsider.com

My late 2018 Mac Mini has 4 Thunderbolt 3 ports, and devices can be connected to them with a USB-C connector. The "bus" for those Thunderbolt 3 ports is USB 3.1, and by what I am reading via the sub-link:

USB 3.0 & USB 3.1 merger into USB 3.2 branding by overseers further confusing USB-C | AppleInsider

The USB Implementers Forum (USB-IF) has muddied the waters surrounding how different USB standards are named, with USB 3.0 and USB 3.1 set to become different generations of USB 3.2, while USB 3.2 itself will become the more confusingly named "USB 3.2 Gen 2x2."

appleinsider.com

it has a technical name of USB 3.2 Gen 2, with a Bandwidth of 10GPS.

So does my Mac Mini support USB 3.2 Gen 2? Also, when I get some data on the T7 and connect it to my Mac Mini, is thee any software I can use to measure the Read and/or Write speed?

 

[chabig]

Your Mac Mini does have four Thunderbolt 3 ports. We can call them that because they support the Thunderbolt 3 data transfer protocols up to 40Gbps. According to Apple, they also support USB 3.1 Gen 2 speed up to 10Gbps. Both "Thunderbolt" and "USB 3.1 Gen 2" and protocol names. The name of the physical slot shaped port is USB Type C.

USB names have become confusing too. USB 3.1 was introduced in 2013. USB 3.2 was introduced in 2017. Both USB 3.1 Gen 1 and USB 3.2 Gen 1 support 5Gbps. USB 3.1 Gen 2 and USB 3.2 Gen 2 support 10Gbps.

USB 3.1 vs USB 3.2-Difference between USB 3.1 and USB 3.2

This page compares USB 3.1 vs USB 3.2 versions and mentions difference between USB 3.1 and USB 3.2.

www.rfwireless-world.com

Your Samsung T7 drive is a USB device. That's why you see it connected to USB in System Information. It supports USB 3.2 Gen 2 up to 10Gbps. It is backwards compatible, so when you connect it to your Mini you get 5Gbps (because that's the limit of the USB on your Mini).

 

[brianmowrey]

Back to OP, it seems like you have a problem with volumes on both drives, whose resolution is to erase/reformat. Although the second drive became unreadable post repair, it seems like the volume was corrupt before you touched it with Disk Util. It seems like both are sharing some corrupted content, e.g. a large app support folder or app library, which explains both going belly-up in concert.

But I use "seems" for all of these, because your description doesn't include a single erase/reformat attempt to prove the point. You are clearly more interested in recovery of your latest progress than diagnosis. I won't say you're wrong to focus here, since the data corruption could also be in your most recent backup anyway.

Still, I would pick the "secondary" drive to reformat since it doesn't seem (per your description) to allow you to access the lost week of work anyway. Then, if the reformatted secondary drive handles OS reinstall without a problem, you'll have an idea if the data in both the original drive and your backup still contains the corruption.

 

[honestone33]

Your Mac Mini does have four Thunderbolt 3 ports. We can call them that because they support the Thunderbolt 3 data transfer protocols up to 40Gbps. According to Apple, they also support USB 3.1 Gen 2 speed up to 10Gbps. Both "Thunderbolt" and "USB 3.1 Gen 2" and protocol names. The name of the physical slot shaped port is USB Type C.

USB names have become confusing too. USB 3.1 was introduced in 2013. USB 3.2 was introduced in 2017. Both USB 3.1 Gen 1 and USB 3.2 Gen 1 support 5Gbps. USB 3.1 Gen 2 and USB 3.2 Gen 2 support 10Gbps.

USB 3.1 vs USB 3.2-Difference between USB 3.1 and USB 3.2

This page compares USB 3.1 vs USB 3.2 versions and mentions difference between USB 3.1 and USB 3.2.

www.rfwireless-world.com

Your Samsung T7 drive is a USB device. That's why you see it connected to USB in System Information. It supports USB 3.2 Gen 2 up to 10Gbps. It is backwards compatible, so when you connect it to your Mini you get 5Gbps (because that's the limit of the USB on your Mini).

Thanks for the explanation.

Interestingly, when I connected the T7 to one of the Thunderbolt Ports and ran Blackmagic Disk Speed test, it was consistently showing a read speed of above 900 MB/s, but the Write speed started close to 900 MB/s, but then was going down, then up. When I connected it to one of the USB ports, Blackmagic showed 418 MB/s Read, and 412 MB/s Write.

I wonder if there is any difference using a smaller partition on the T7 (it's not partitioned yet). I'll have to try that, along with having some actual data on two of the partitions. (For the Big Sur partition I plan on having, and installing Big Sur on it, apparently Blackmagic cannot be used on such a partition, as it will be read only. That's what I got when I tried to use Blackmagic on my Samsung 850 Pro 512 gig SSD and the partition containing the SuperDuper! backup of my Mac Mini. But for the partition that just has Miscellaneous folders, files, etc., I could run it).

One other thing: only a Roku Ultra device contains a USB port.

 

[honestone33]

Back to OP, it seems like you have a problem with volumes on both drives, whose resolution is to erase/reformat. Although the second drive became unreadable post repair, it seems like the volume was corrupt before you touched it with Disk Util. It seems like both are sharing some corrupted content, e.g. a large app support folder or app library, which explains both going belly-up in concert.

But I use "seems" for all of these, because your description doesn't include a single erase/reformat attempt to prove the point. You are clearly more interested in recovery of your latest progress than diagnosis. I won't say you're wrong to focus here, since the data corruption could also be in your most recent backup anyway.

Still, I would pick the "secondary" drive to reformat since it doesn't seem (per your description) to allow you to access the lost week of work anyway. Then, if the reformatted secondary drive handles OS reinstall without a problem, you'll have an idea if the data in both the original drive and your backup still contains the corruption.

Sorry about veering somewhat off-topic.

Interesting post. And excellent idea about concentrating on the problematic Volume.

 

[chrfr]

Your Mac Mini does have four Thunderbolt 3 ports. We can call them that because they support the Thunderbolt 3 data transfer protocols up to 40Gbps. According to Apple, they also support USB 3.1 Gen 2 speed up to 10Gbps. Both "Thunderbolt" and "USB 3.1 Gen 2" and protocol names. The name of the physical slot shaped port is USB Type C.

USB names have become confusing too. USB 3.1 was introduced in 2013. USB 3.2 was introduced in 2017. Both USB 3.1 Gen 1 and USB 3.2 Gen 1 support 5Gbps. USB 3.1 Gen 2 and USB 3.2 Gen 2 support 10Gbps.

USB 3.1 vs USB 3.2-Difference between USB 3.1 and USB 3.2

This page compares USB 3.1 vs USB 3.2 versions and mentions difference between USB 3.1 and USB 3.2.

www.rfwireless-world.com

Your Samsung T7 drive is a USB device. That's why you see it connected to USB in System Information. It supports USB 3.2 Gen 2 up to 10Gbps. It is backwards compatible, so when you connect it to your Mini you get 5Gbps (because that's the limit of the USB on your Mini).

The 2018 mini supports 10Gbps USB-C connections without a problem. USB 3.1 gen 2 has, for some inexplicable reason, been renames USB 3.2 gen 2. This is a 10 gigabit connection.

 

[chrfr]

Thanks for the explanation.

Interestingly, when I connected the T7 to one of the Thunderbolt Ports and ran Blackmagic Disk Speed test, it was consistently showing a read speed of above 900 MB/s, but the Write speed started close to 900 MB/s, but then was going down, then up. When I connected it to one of the USB ports, Blackmagic showed 418 MB/s Read, and 412 MB/s Write.

I wonder if there is any difference using a smaller partition on the T7 (it's not partitioned yet). I'll have to try that, along with having some actual data on two of the partitions. (For the Big Sur partition I plan on having, and installing Big Sur on it, apparently Blackmagic cannot be used on such a partition, as it will be read only. That's what I got when I tried to use Blackmagic on my Samsung 850 Pro 512 gig SSD and the partition containing the SuperDuper! backup of my Mac Mini. But for the partition that just has Miscellaneous folders, files, etc., I could run it).

One other thing: only a Roku Ultra device contains a USB port.

The USB-C ports support 10 gigabits per second while the standard USB ports are only 5Gbps, which is why you’re seeing the difference. The T7 isn’t a Thunderbolt device.