I have a disk that won't mount

[machenryr]

I had to pull out my trusty Disk Warrior and update it to the latest - 5.3.2. I was sure that would fix it but no. It says "Directory cannot be rebuilt because it uses an unsupported version of APFS." OK. Is there another solution. It's a 4TB almost full disk. A lot has been backed up but my backup system I allowed to fall out. This is my second warning. This is an external disk. Any ideas and help would be very much appreciated!

 

[Fishrrman]

What Mac do you have?
What year was it made?
What version of the OS is running?

What is the format of the problem drive?
Has it been partitioned, or anything along that line?
Have you tried mounting it on a DIFFERENT Mac?

If it was used for backups, what backup utility did you use?

 

[machenryr]

What Mac do you have?
What year was it made?
What version of the OS is running?

What is the format of the problem drive?
Has it been partitioned, or anything along that line?
Have you tried mounting it on a DIFFERENT Mac?

If it was used for backups, what backup utility did you use?

Thank you. It's all in my signature. 2025 Mac Studio M4 Max. Sequoia 15.7.7. APFS. Nothing has been partitioned. I have not tried on a different Mac. Thanks

 

[machenryr]

The other thing is this SSD, Toshiba 4TB, was purchased last year in January 2025. It's not that old. Everything is new. Although too old for a warranty.

 

[DLary]

Disk Warrior is unable to work with any version of an APFS drive. Have you tried repairing the disk while you are booted into recovery mode?

 

[machenryr]

Disk Warrior is unable to work with any version of an APFS drive. Have you tried repairing the disk while you are booted into recovery mode?

Thank you. No I haven't. In lieu of that is there any other recovery app that I can try?

 

[Fishrrman]

"In lieu of that is there any other recovery app that I can try?"

I could be wrong, but since Apple keeps "the inner workings" of APFS under wraps, I don't think there is ANY 3rd-party software that can actually "repair" APFS drives.

Again, I could be wrong, and I welcome correction from others.

This Toshiba drive...
Did you buy it as a "bare" drive, and then put it into an enclosure?
If possible, have you tried the drive in a DIFFERENT enclosure, or perhaps in a USB3/SATA docking station?

 

[machenryr]

"In lieu of that is there any other recovery app that I can try?"

I could be wrong, but since Apple keeps "the inner workings" of APFS under wraps, I don't think there is ANY 3rd-party software that can actually "repair" APFS drives.

Again, I could be wrong, and I welcome correction from others.

This Toshiba drive...
Did you buy it as a "bare" drive, and then put it into an enclosure?
If possible, have you tried the drive in a DIFFERENT enclosure, or perhaps in a USB3/SATA docking station?

I wish I knew this about APFS. I always take a minute to decide which format to use. I used to get OWC enclosures but this is a 4TB external, no enclosure.

 

[hobowankenobi]

The good news is that APFS has much less directory or other structural issues to fix.

The bad news is...there are no good tools outside of Disk Utiliy (that I am aware of) to help should the need arise.

If DU can't fix a drive, I would assume a hardware problem, and would want to immediaetly work on data recovery if needed, and then format the drive and test test test before using to store anything import.

 

[hobowankenobi]

I wish I knew this about APFS. I always take a minute to decide which format to use. I used to get OWC enclosures but this is a 4TB external, no enclosure.

It is involved...but interesting info here to know the difference. Note the links to lots more APFS details towards the bottom of the page. Lot's of deeper dive comments on these pages too.

 

[Fishrrman]

OP wrote:
"this is a 4TB external, no enclosure."

No enclosure?
Then... how is it connected to the Mac?

 

[Skwoodge]

Have you tried Disk Drill? https://www.cleverfiles.com/

As others have said, Disk Warrior doesn't support APFS. If you want to keep Disk Warrior around, format your external drives as HFS.

 

[machenryr]

OP wrote:
"this is a 4TB external, no enclosure."

No enclosure?
Then... how is it connected to the Mac?

Duh. Meaning I used to buy enclosures from OWC and install the drives myself. These are ready made. Just a little small box with USB connection.

 

[LeVan]

Duh. Meaning I used to buy enclosures from OWC and install the drives myself. These are ready made. Just a little small box with USB connection.

I second that suggestion to try that drive in a different encolure. They are not all equal. One alternative is a cheap Orico case available on Amazon. I have 2 such cases for 2.5" SSDs, but they also make cheap cases for M2 blades.
All USB enclosures for external SSDs have 2 things in common, a physical case or box to mount the SSD securely and a USB port (normally USB-C or USB-A), but they all have firmware that handles the data transmission, and that can vary from company to company.
The Orical cases are cheap, but they work well, so in this case they are a good choice for a second alternative case.

ORICO 2.5'' External Hard Drive Enclosure USB 3.0 to SATA III Tool-Free Clear Hard Disk Case for 2.5 inch 7mm 9.5mm SATA HDD SSD Max 6TB Support UASP(2139U3)

Wide Compatibility - This ORICO SATA hdd enclosure helps to connect your 2.5inch SATA I/II/III hard drive SSD to PC, Laptop, TV and PS4. The hard drive enclosure is suitable for 2.5 inch 7mm/9.5mm 4TB SSD hard drives, and is compatible with Windows, LINUX and Mac OS and above systems.

www.amazon.com

Then once you get access to the drive: In macOS Yosemite or later: the terminal code below will enable TRIM, which notifies the computer's OS that a file space has been deleted, speeding up any subsequent writes to that area and keeping the disk write speeds healthy.

Code:
sudo trimforce enable

USB devices will normally not have TRIM enabled, as it is only supported on a drive connected to a Thunderbolt port or an internal drive.

However, if the UASP protocol is supported on the USB device, TRIM will work. The Crucial MX500 series has this UASP protocol enabled.
To check if UASP is enabled on a currently connected USB devices, use the following command using the Terminal;

Code:
ioreg | grep UAS

If that doesn't show anything, try the following procedure.

Connect the USB device, reboot with the device connected, then use the following code in Terminal; Note: this command can take 15 seconds or more on a 512GB SSD.

Code:
log show --predicate "processID == 0" | grep spaceman | grep -i trim
or
log show --debug --last boot --predicate "processID == 0" | grep trim
log show --debug --last boot --predicate "processID == 0" | grep -e "blocks free in" -e "blocks trimmed"

All of the commands above show Trim is enabled on the Crucial MX500 SSD in a cheap Oraco clear plastic USB 3.1 enclosure.