Netbackup thinks media is write protected but media has been previously written to

[harrisv]

We are running nbu 6.5.4 and have noticed on a couple of occasions that a tape that has valid
images on it,  will report that the media is write protected when attempting to append to the
tape.  Has anyone else notice this behavior???

[J_H_Is_gone]

A tape can have been written to and have valid images on it AND be write protected.

Can I be so bold to ask if you looked at the physical tape and verified if it is write protected or if there is anything obstructing the opening?

[harrisv]

It's strange because the tape was written to earlier today.  The tape's write protect switch was reset after the occurance of the
error. 

[Andy_Welburn]

The write-protect tab had been nudged only very slightly, but that was enough for the library tp report it as being write-protected!