"The disk you inserted was not readable by this computer." errors

[halloleo]

I have ywo older external USB hard drives, one of them I think I had used as Time Machine backup for my Catalina iMac. The other one, I'm not sure what I had on it. One of the driveswas a 2-disk RAID which I used in Mirrored mode.

Now half a year later, I connect both drives to my new M2 Mac mini, and I get the error:

(The disk you inserted was not readable by this computer.)

I clicked "Eject" and connected the two drives to the old iMac. - There I get the same error message! Very concerning! Drives corrupted? I am skeptical about this because two drives show this behaviour at the same time...

In Disk Utility the three disks (two from one drive and one from the other drive) show up like this:

How to explain it? Are both drives still ok, just some macOS updates got in the way? If so, with what tool can I read the drives again. Or are both drives really corrupted? How can I check?

Thanks for any pointers!

 

[kinga]

Remember, the error message doesn't guarantee permanent data loss. With careful troubleshooting and potentially some data recovery efforts, you can reaccess your files. Be patient and methodical, and prioritize data backup before attempting potentially data-erasing solutions.

 

[casperes1996]

What file systems are on them? (See when selected in disk utility)

 

[halloleo]

What file systems are on them? (See when selected in disk utility)

Well, there doesn't seem to be much to see in Disk Utiliy: Here what it shows for each drive:

First disk:

Second disk (shows up as two individual drives because of RAID):

Can I get the file system type from these? (I think they were HFS+ in any case.)

 

[casperes1996]

Well, there doesn't seem to be much to see in Disk Utiliy: Here what it shows for each drive:

First disk:

View attachment 2337533

Second disk (shows up as two individual drives because of RAID):

View attachment 2337535
View attachment 2337536

Can I get the file system type from these? (I think they were HFS+ in any case.)

Could you run me `diskutil list` in a Terminal and show the output here? It gives more detail about all disks it sees.

At least this confirms they are GUID.

Do you remember how you set up RAID? Apple Software RAID?

 

[halloleo]

Could you run me `diskutil list` in a Terminal and show the output here? It gives more detail about all disks it sees.

I got for these disks:

/dev/disk4 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *18.0 TB    disk4
   1:           Linux Filesystem                         18.0 TB    disk4s1

/dev/disk5 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *6.0 TB     disk5
   1:           Linux Filesystem                         6.0 TB     disk5s1

/dev/disk6 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *6.0 TB     disk6
   1:           Linux Filesystem                         6.0 TB     disk6s1

The Linux Filesystem info got me thinking... and I remembered that I had used these disks as backup on my (Linux) NAS , not on my Mac. This explains it.

Thanks for your hand-holding to find these details!

 

[casperes1996]

I got for these disks:

/dev/disk4 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *18.0 TB    disk4
   1:           Linux Filesystem                         18.0 TB    disk4s1

/dev/disk5 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *6.0 TB     disk5
   1:           Linux Filesystem                         6.0 TB     disk5s1

/dev/disk6 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *6.0 TB     disk6
   1:           Linux Filesystem                         6.0 TB     disk6s1

The Linux Filesystem info got me thinking... and I remembered that I had used these disks as backup on my (Linux) NAS , not on my Mac. This explains it.

Thanks for your hand-holding to find these details!

Sure thing. There are macOS tools to read ext3/4 file systems. They’re a bit janky though. At least the ones I know. Might be easier to just hook the drives up to a Linux box if you have one available. Then either extract the data you want from there or set up file sharing to access the drives though the Linux machine.

If you want to access the disks directly from macOS look up extfuse. Think that’s what it’s called. Requires macfuse/osxfuse. And of course doesn’t work if the Linux file system is btrfs or something else.