>The library always work perfectly and the configuration in tivoli is ok.
>The number of drives is 1 and the mount limit is set to one.
>Any ideas?

Hello

Execute  "q path" and/or "q drive" command and check whether all related
devices are online.

What is the platform where TSM is installed on ?  AIX ?

I had a similar problem after some messing with san environment which
altered the numbering of  "/dev/smcX" and "/dev/rmtX" device files.

kind regards

Pawel W