This has mostly likely happened because of some filesystem corruption, where the recovery process includes some risk (usually just a small one) of data loss.
Just to cover the worse case scenario, I would recommend that you obtain a bootable Endless USB disk (or other Linux) and use it to boot and save any important documents that are accessible there.
After that, you can perform the recovery operation, and you have two options:
- Using a bootable live Endless USB disk, open the Disks app. Find your disk on the left, then click on the large ostree partition showed on the right. You’ll see an icon with two gears right below that - click it and then select “Repair filesystem”
You’ll need another computer here in order to create the bootable Endless USB disk. But once you’ve got that you at least can perform the backup and repair under the comfort of a graphical user interface.
- Alternatively it is possible to perform the filesystem repair directly from the textual terminal that you’re looking at.
You can see instructions for that here:
My pc doesn't start after the os update
Be sure to not have any Endless USB disks connected at this point. The command you want in this case is fsck /dev/disk/by-label/ostree
Then reboot and hopefully it boots back into Endless again.
I apologise for the hassle here - our reporting and handling of this type of filesystem corruption is lacking, and we’re working to improve this for the future.