How to stop OS X from trying to init Linux volumes

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Level 1

4 points

How to stop OS X from trying to init Linux volumes

How do I stop OS X Sierra from trying to mount my Linux drive every time it boots? Seeing a dialog "this disk is not readable, Initialise, Ignore, ..." is not much helpful on each boot, not even mind if somebody clicks on the Initialise and ruins the whole Linux install by accident.

Obviously, I tried the (still deprecated?) fstab route, but for that, I need the volume UUID. To get that, I need to MOUNT the volume. Still obviously, I can't mount the volume because OS X does't read EXT filesystem.

Kind of Catch-22, ain't it?

I could try to specify the volumes in fstab by mountpoint (/dev/disk2s1), but that is quite viable to change and could break havoc with the system if the mountpoints changed.

Thanks for any help.

macOS Sierra (10.12.4)

Posted on Jun 30, 2017 1:14 AM

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Answer 1

Jun 30, 2017 3:54 AM in response to canis68K

See if this helps.

Go to the Apple menu and select 'About This Mac'
Now click on 'System Report'
This will launch the System Information utility
In System Information utility, select SATA/SAS
It should list at the top the drive or drives
Select the drive in question i.e. the one containing the Ext3 or Ext4 partition
It should then below list all the volumes on that drive and detail each volume/partitions UUID number

Whilst I don't have a drive with a Linux Ext3 or Ext4 partition on it the above unlike other methods e.g. diskutil in Terminal it lists the UUID for the hidden EFI and Recovery HD partitions even though they are not mounted. I am therefore hopeful it will list the Ext3 or Ext4 partition for you as well.

Note: CoreStorage volumes e.g. a FileVault encrypted volume will not show a UUID using the above method but this will not apply to a Linux Ext3 or Ext4 volume.

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Answer 2

dialabrain

Level 10

122,549 points

Jun 30, 2017 2:01 AM in response to canis68K

FWIW, since macOS can neither read nor write to Linux formatted drives it will always offer to reformat the drive. You would have to use something like Paragon ExtFS in order for it to mount, read and write.

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Answer 3

canis68K Author

Level 1

4 points

Jun 30, 2017 3:08 AM in response to dialabrain

Thanks, I am aware of such drivers. But I do not want to mount and read the filesystem, I want to prevent OS from trying to initialise it upon boot, since it has no need. That can, AFAIK, be only done by editing etc/fstab, and writing the UUID of the volume there with the option to ignore it. But without mounting the volume, I can't get the UUID. Catch 22. I guess I could read the UUID in Linux itself, would that work? Thanks.

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Answer 4

canis68K Author

Level 1

4 points

Jun 30, 2017 8:27 AM in response to John Lockwood

Thank you, I will try that when I get back to the computer. In case System Information doesn't show the UUID either, I think I could try extracting the UUID from within Linux using blkid command, and using the value in MacOS's fstab file. Hope that works. Still, it is quite convoluted way... 😟

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