I have a problem in that the current "filling" tape gets set to unavailable
....

Does anyone have any idea what would automatically set a active filling tape
to an unavailable status ?

This is not a one time occurrence it happens all the time and the system
then requests a scratch tape. If I cancel the migration set the tape to
read/write and restart the migration process it woks fine. All throughout
the day I check the status until I leave and it remains read/write. When I
return in the morning it's status is unavailable and the system is waiting
for a scratch tape.

Thanks for any help in advance.

John