RESOLVED - My original USB died and I just needed to pull down the backup made right before the upgrade, manually extract it to a new USB (the unRAID USB Creator was not doing it properly for some reason), boot up and import the key. I'm back up and running.

Just upgraded to 7.2.2 and it's not booting (see screenshots). It says the following and then say "hit enter to reboot". I'm going to continue troubleshooting and would prefer not have to reinstall the flash drive if avoidable. Please help.

umount /dev: target is busy
umount /: not mounted

not found - press ENTER key to reboot...

Edited December 1, 2025Dec 1 by Mat W

Looking at the screenshots, it looks like maybe the USB image got corrupted during the upgrade given the I/O errors for sda?

The screenshot definitely shows an issue with reading the flash drive. I would suggest downloading the zip file for the release and then extracting all the bz* type files overwriting the ones in the root of the flash drive. That often seems to help with this type of error happening just after an upgrade.

If that does not help you may have a genuine issue with the flash drive. While doing the action mentioned above I would recommend taking the opportunity to also make a backup of the ‘config’ folder from the flash drive as that contains all your configuration information.

Problem I'm fighting now is getting windows to mount it, which I'm guessing might point at the USB being corrupted and not just some files. Will continue to fight with it, great way to start a Monday.

Edited December 1, 2025Dec 1 by Mat W

1 minute ago, Mat W said:

Problem I'm fighting now is getting windows to mount it... great way to start a Monday

Unfortunately that suggests an issue with the flash drive as is in FAT32 format which is something Windows should have no problems with.

Yup.  Thankfully it backed up successfully during the upgrade process!  Might just stop fighting with the USB drive with an unknown age ;)

Just now, Mat W said:

Yup.  Thankfully it backed up successfully during the upgrade process!  Might just stop fighting with the USB drive with an unknown age ;)

Good to hear you have a backup so recovery should be relatively painless.

I think that an upgrade is one time that a considerable amount of data (I think around 800MB with latest Unraid release) is written to the flash drive so making it more likely to push a borderline drive over the edge.

I've been in IT for 30 years and I can't count the number of times I've seen a reboot trigger a drive failure.

Ugh.  System isn't booting as if the USB drive isn't bootable.  Take it back over to Windows and run make_bootable.bat as admin and it complains that syslinux executable not found.

Ok... So after much troubleshooting, I determined that the unRAID USB Creator was not working properly and did not install all of the folders and files from the USB backup I pulled down from Connect.  Unsure why it is failing but unzipping the Flash backup shows all of the expected files/folders.  I am in the process of manually extracting to the USB drive now.  Will update again once it is complete and I have attempted to boot.

Last update: End result, my old USB decided to leave the chat AND the unRAID USB Creator decided it didn't want to fully create the new USB so I had to manually create it by extracting my backup to the new USB drive.  Booted right up, imported key and I am back in business as if nothing went wrong.

Side note: the nVidia driver was missing and had to be reinstalled but after a reboot all was happy.

I'll update my original post for historical purposes.