When initiating manual backups or occasionally when automatic/scheduled backups run, a user may notice that Windows Server Backup may appear to “hang” when the status is reporting: “Preparing media to store backups…”.
In some rare cases, it may actually be in a hang state, however most of the time, it’s actually consolidating and/or checking previous backups on the destination media.
To Confirm this:
Open the Task Manager as Administrator, then click on the “Performance” tab, click on “Open Resource Monitor”. Flip over to the “Disk” tab, expand “Disk Activity”, and sort by name. You should see the read requests on the destination media, you’ll also notice that it is slowly progressing consecutively through each backup set (increments of 1, accessing multiple at a time).
This confirms that the Windows Server Backup services are functioning and it is in fact running. In one case, I had 723 previous backups, and it took around 50 minutes to count from 1 to 723, and then the backup finally proceeded.
I have also seen this occur when a previous backup failed or was cancelled. This occurs with Windows Server Backup on Windows Server 2008, Windows Server 2008 R2, and Windows Server 2012 R2.