RDX drive issue

Please find the below specification as we have in our environment.

Windows Server 2008 R2
Backup Exec 2012
RDX drive & Cortridges
USB KVM Switch

I have some concern related backup exec & Storage.

Backup is not target to storage untilled we remove the USB KVM switch.
Meanwhile after removing KVM Switch from the server backup is working fine & when we attached KVM switch on server backup is not targets to storage and backup goes as queued.

Please advise