HSM for Windows migrated files may expire after 365 days on the TSM server. The client should be configured to use a mangement class with an archive copy group retention set to a value larger than 365 days or to NOLIMIT.
Tivoli Storage Manager (TSM) HSM for Windows migrates files to the archive pool on the TSM server. The migrated files are bound to management class. And if you did not change the archive copy group's retention period of this class, then the retention period is 365 days.
This means that 365 days after the files have been migrated to the TSM server for the first time they are expired and deleted. The files are lost then, unless you have taken backups using the TSM backup-archive client.
If you want to keep migrated files longer than 365 days, then extend the retention period by updating the archive copy group of the management class used. Change the value for the RETVER parameter to a value larger than 365 or even to NOLIMIT. NOLIMIT prevents that files are expired and deleted, unless they are deleted on the HSM client's file system. Afterwards activate the policy set used.