I'm sorry about the delay in a response to this thread. I'm seeing it for the first time today.
When backing up SmarterMail, the files we recommend preserving are:
- All .xml and .dat files found in the Service directory folder (default installation path: C:\Program Files (x86)\SmarterTools\SmarterMail)
- All SmarterMail domain folders (default installation path: C:\SmarterMail\Domains)
You can choose to omit the indexing files from your backup. Just keep in mind that while SmarterMail will automatically recreate the index folder, only new messages will be indexed, so searching for existing messages would not work. The same would apply for the calendar, contacts, tasks and notes until one item in each of those collections is edited. (The edit would cause those collections to fully reindex.)
So in short, if you do not backup the index files, I would recommend manually reindexing the user's account if you have to restore it from backup. Mail is the most likely thing to be searched for, and all old messages will not be searchable until they reindexed. (You can reindex a user by logging in as the Domain Admin and going to Settings > Domain Settings > Users. Highlight the user and click Reindex in the toolbar.)
Hope this helps!