why Outlook thinks the ost is outdated

Hi there,

In several cases, I have encountered outlook 2007 telling me that an ost is outdated, and I should delete and regenerate a new one.   In the most recent case, I cloned a disk and do the swap in three days.  So the ost is three days behind, outlook did not like it.

does anyone know whether there is a threshold for outlook to determine how old is too old for an ost file?  Is there anyway to change that threshold or force outlook to use the old ost file and just synch the difference?

I usually recommend users to delete and regenerate, which is the cleanest way.  But in a few cases, the user mailbox is very big and a full synch cross WAN is something I try to avoid.

Thanks.