Jed,
I think it is probably backing up one of the bigger tables, as the
application have to get the data from the table, save it on a file and
append into the compressed file. Hence it might take little longer.
Please send us sdbackup.log found under
\Manageengine\ServiceDesk\bin if you still have no progress.
You can mail us the file to servicedeskplus-support@manageengine.com
