Note to self: Have to look up the exact messages and add them here.
Normally this occurs when deleting too many files using the trash in the empty trash phase. So because of some strange reason mac OS wants to show you the number of files to delete and starts counting them. Well many files are hard to count, right?! So it takes time and time… and you decide to cancel (stop) the process. Well now you have a non dismissable window on your screen that takes a lot of time until it disappears. So you will probably restart and then when you try to empty again the trash… guess what that happens again.
When the window is open trying to stop the empty trash action just move the folder with too many files outside of the .Trashes folder.
Here is how I did it:
1. Open a terminal
2. Run the command
sudo mv /Volumes/BackupDisk/.Trashes/501/Backups.backupdb /Volumes/BackupDisk/
3. To actually delete the files run the command:
sudo rm -rf /Volumes/BackupDisk/Backups.backupdb
Have a nice life!