Drive reported bad, checked cable, restarted, drive still bad - but it isn't

Today I had to move my server to a different location. After the move and during the reboot, a bad disk was reported on the console and in the Web-UI.

I did stop and shutdown the server.

I opened the case, saw a cable hanging down, put it in and restarted.

The error on the console is gone, but Web-UI still reports a faulty disk.

I did stop the server again and issued a SMART short-test for this disk. The disk is ok but still reported as bad on the Web-UI.

What's the correct way to bring this disk up again?

Thanks in advance.

tower-diagnostics-20150905-1112.zip

Once a disk has been disabled by unRAID (the red x) then the only way to remove this is to rebuild the disk.  This can either be onto a different disk, or if you think the disk is OK back onto the same disk.  The red 'x' indicates that unRAID is simulating the disk using the other disks plus parity.

If you want to rebuild the disk onto itself then the procedure is:

• Stop the array
  
• Unassign the disk and start the array.  You will be told that the array will be unprotected but continue anyway.  This step is to get unRAID to 'forget' the current disk
  
• Stop the array and assign the disk again.    You will be told that the disk will be rebuilt if the array is started, so go ahead and start it and let the rebuild run.
  

When the rebuild completes OK the red 'x' will be removed.

Just to elaborate a little.

unRAID disables a disk because a write to it failed. Even if the disk is OK, its data is not. Thus a rebuild is required.

Thanks a lot. Disk is rebuilding.

This unRAID tower - the first out of two - is from 2007. But whenever something happens the required steps are forgotten.