What does expired, or inactive TSM files mean?

Here is how status of active, inactive and expired files work:

Once your file is backed up to the TSM server, the status of the file on the TSM server is 'active' and remains 'active' until the file is changed or deleted on your machine, and the subsequent backup notices the change and tells the TSM server that the file has changed or been deleted from your machine.

If the file was changed, a new version is backed up and becomes the 'active' version, and the old version is expired and becomes 'inactive'. If the file was deleted on your machine, the only change in TSM is that the the old version is expired and becomes 'inactive'.

'Inactive' files remain on the TSM server and available to restore for 30 days, after which they are automatically deleted.

If the file never changes on your machine, once it is backed up to the TSM server, the status will remain 'active' and be available for restore, as long as partition on which it resides has been backed up in the last 180 days.