I had a user who was missing their Personal Address Book and Frequent Contacts Address Book. I tried many things, but the only way to fix this issue was;

1) Archive all their mail.
2) Deleted the mailbox.
3) Re-create the mailbox (new FID of course).
4) Address Books OK now.
5) Use GWFID fixer utility to rename archives to new FID.
6) Un-archive mail.

All went OK.

Next day user calls and complains they're missing about a months worth of archived Sent Items. No problem, so I try restoring the archives ... NOTHING THERE ! Our backup guys are working on that issue.

So, I decide to "Recover the Deleted Account" from the day before I did the above work (to grab that months worth of Sent Items) by changing the Post Office to Direct/Client Server, rebuilding, and mapping to the restored Post Office location.

Problem is, I can't recover because the new one exists that I created in Step 3 above.

Any Ideas ?