It has to be said we don’t get MANY Sharepoint Archiving escalations in to Engineering, well, we didn’t before the beginning of this year. We now seem to get a reasonable number, and some issues are really interesting.
One that I worked on a little while ago eventually led to a 9.0.2 hotfix, see below for the reference. The issue is that over a period of time, in some installations of EV/Sharepoint, retrieval of archived items would just stop. It can be brought on by end-users, or by Sharepoint indexing (if the indexing touches archived items).
It boiled down to handled of objects, and the freeing up of them at the end of their usage (or rather not freeing them up in this case).
So if you have Sharepoint 64 bit, and are archiving Sharepoint with Enterprise Vault you will get this issue, and previous versions to 9.0.2 are also affected. The fix is straight forward, but it’s a binary change, and the hotfix is only available for post 9.0.2.