Outlook sync issues

I have outlook syncing for all users through the less than dsirable client sync. But if the workstation is unattended for any length of time, even if outlook is viewing email rather than calendar for a while, the sync fails, all that needs to happen is refresh the calendar view in outlook and it works again.... trying to install it on the server and sync unattended fails for the same reason. I've searched high and low for a setting to resolve this without luck... anyone else resolved this problem?
--it's really time for commit to use activesync --

We are not aware of such an issue and it sounds like the permission to the calendar folder somehow expire once you are not displaying the calendar. It should make no different what folder is displayed in Outlook, unless permission is denied for the sync after a while. Maybe it worth reviewing all related security policies.