Disk you inserted is not readable by this computer.

[grafviktor]

Hello all!

My computer has two HDDs, the secondary one contains ext4 and linux swap partitions. Unfortunately macos Sierra keeps showing me an error message that Linux partition "... is not readable by this computer" on every computer boot. I tried to edit /etc/fstab and set noauto flag to these partitions, unfortunately, it seems, that this method doesn't work in Sierra. Do you have any clues how to get rid of this message ? Thank you. 

 

Apologize if that was asked already by someone else, but I was unable to find the answer.

[redneck]

only thing i can think of is type of format . Windows does the same with mac Efat. 

[grafviktor]

Thank you very much for your reply, redneck.

Unfortunately, I can't afford to erase Linux disk :-\ But I'm more than sure that my problem can be resolved in some another way - anyway macos is still UNIX and, basing on my humble experience, there's nothing impossible in these kind of systems :-)

[nawcom]

using /etc/fstab to prevent automounting still works in Sierra. In fact I use that myself to prevent automounting certain NTFS partitions in Sierra. However just like on any unix system, the fstab file is used to set automounting parameters for filesystems that it supports.

 

The error you're getting is as far as I know something you can't get rid of via some DiskArbitration setting or anything like it and as long as OS X lacks an ext4 filesystem driver, or for any unsupported filesystem for that matter, you'll get the nag once you enter the desktop. I dealt with this when I had a disk with an unsupported filesystem on it and just lived with that annoying error.

 

Luckily you can install ext4 support. In Sierra your choice is either fuse-ext2 which supports ext4 through FUSE for macOS, or Paragon ExtFS which is commercial. With ExtFS, getting it to use the filesystem drivers while removing the Trial nag is of course something that can't be discussed here, but it's possible.

 

I use Paragon ExtFS and preventing automounting works fine. Find the Volume UUID either through Disk Utility or command line diskutil. Since mine is disk1s1 I used

nawcoms-MacBook-Pro:~ nawcom$ diskutil info /dev/disk1s1
   Device Identifier:        disk1s1
   Device Node:              /dev/disk1s1
   Whole:                    No
   Part of Whole:            disk1

   Volume Name:              Untitled
   Mounted:                  No

   Partition Type:           Linux
   File System Personality:  UFSD_EXTFS3
   Type (Bundle):            ufsd_ExtFS
   Name (User Visible):      Extended Filesystem 3

   OS Can Be Installed:      No
   Media Type:               Generic
   Protocol:                 USB
   SMART Status:             Not Supported
   Volume UUID:              9485E394-BB0A-B841-054A-175E2A94002E

   Disk Size:                31.3 GB (31259656192 Bytes) (exactly 61054016 512-Byte-Units)
   Device Block Size:        512 Bytes

   Volume Total Space:       0 B (0 Bytes) (exactly 0 512-Byte-Units)
   Volume Available Space:   0 B (0 Bytes) (exactly 0 512-Byte-Units)

   Read-Only Media:          No
   Read-Only Volume:         Not applicable (not mounted)

   Device Location:          External
   Removable Media:          Removable
   Media Removal:            Software-Activated

Note: even though it mentions ext3 this is very much ext4.

 

Here's the line that I'm using in /etc/fstab:

UUID=9485E394-BB0A-B841-054A-175E2A94002E	none	ufsd_ExtFS	ro,noauto

And as a result it does not automount. Without this fstab line, it automounts.

 

So there you have it. Your choices are either:

• Don't install ext4 filesystem support and deal with the nag, or
• Install ext4 filesystem support and prevent it from mounting at boot. But to be honest, if you can mount it (read-only by default) why not leave it be?