Tape drive goes off line when after tape changed

I am runnig a Hyper-V Server 2012R2 system and Backup Exec 2014 is running on one of these virtual machines.

I have an Ultrium LTO6 Tape Drive.

Each time a scheduled job tries to run after a tape change the job fails as the tape drive has gone offline. "The device has been set to offline because the device attached to the computer is not responding" - all I have to do is right click and remove the offline status and restart the job and all runs OK.

How do I prevent this error occuring?

Thanks,

Julian