Hi

On ADSM you got the option within the storage pools to specify
whether you want to use any scratch volumes or you can specify which
scratch volumes to use.
I think your problem is within your storage pools where you are
specifying which scratch volumes 
to use and not randomly choose any scratch volume that's available
within the library.
Make sure about this before doing a library inventory because if you
checkout a volume from
ADSM its database is aware of the volumes being checked out.

Thks Sean
ADSM Administrator
EDS South Africa