JorgeB

Scrub the pool, if all errors are corrected or no errors are detected, reset the stats and keep monitoring, if new errors show up, run memtest.

That suggests either a flash drive issue, or a compatibility issue between the server and the release you installed. If you are using a newer Unraid release, try recreating the flash drive with a version that is known to work with that server, if it still fails to boot, post a photo of where it stops.

If the current pool is a mirror, you could remove one device, create a split bootable pool on it, then move the data from the other device there, and finally add it to the new pool to create a mirror.

Try deleting the /previous folder from the flash drive; that should be enough But if you want to create a boot pool, you just need to run the wizard They need to be unassigned, and any data there will be deleted

Is that with with a stock install?

Btrfs is detecting data corruption; this is typically not a device problem, start by running memtest.

Can't see what's causing the issue, the GUI appears to start correctly after boot, but then it stops working. You can try redoing the flash drive, backup the current one first and then recreate it using the USB tool and just restore the bare minimum, like the key, super.dat and the pools folder for the assignments, also copy the docker user templates folder (\config\plugins\dockerMan\templates-user), if all works you can then reconfigure the server or try restoring a few config files at a time from the backup to see if you can find the culprit.

You can, activation codes can be used with a different account than the one used to purchase it

Insert the flash drive in a PC/Mac and try to copy the config folder; that's all you need.

Try recreating the flash drive, first backup the current one, then recreate it using the USB tool, confirm the flash drive boots with the stock install, and if yes, restore only the /config folder from the backup overwriting any existing files, if it still fails, try with a new one.

This seems unrelated to that; there are actual flash drive errors showing, when it's a partition provlem, Unraid still boots normally; just the GUI won't work, and there's a specific error logged by emhttp.

It's possible the drive is the problem; sometimes SMART can look OK, and the errors are not logged as a disk problem, and it still is.

It's fine to attempt to recreate the existing one first; if that doesn't work, repeat with a new flash drive, but you will then need to transfer the key.

try recreating the flash drive, first backup the current one, then recreate it using the USB tool, confirm the flash drive boots with the stock install, and if yes, restore only the /config folder from the backup overwriting any existing files.

Enable the syslog server and post that after the next crash, together with fresh diagnostics.