We have been backing up our 2008 server using the built in backup utility in Windows.
All of a sudden we get this "The semaphore period has expired". This goes on for a few days. Googling shows that maybe the drives we are trying to backup are too full. The C drive is 80/231 free (35%), the E drive is 304GB free and the R drive is 171GB free.
Another suggestion is the backup drive is bad. Replacing the drive yields the same results.