Hi I got the same problem a few weeks ago. After updating a TSM 3.1 to 4.13. The 3494 mounted a tape once and then the drives are currently available in library and ANR8447E. I deleted the drives from TSM and OS (AIX 4.3.3 .M6 newest ATape and ATLDD ) . Booting the machine. Drives are available one time then the same procedure. Tivoli Hotline could not help. Tracing the server they did'nt find anything. At least I am going back to version 4.1.2 and it worked fine. The same environment at an other customer worked with TSM 4.1.3. Hope it helps frendly regards Felix TranCAT Gmbh & CO KG Germany