Public folder cleanup in Exchange 5.5

I recently had a situation where we had seperated forever some Exchange 5.5 sites. They were never going to be rejoined for directory replication. Never, ever, ever! After separating them, we found a lot of public folders that we could not take ownership of (using the Exchange 5.5 server's DS/IS Consistency Adjuster and choosing to rehome public folders from unknown sites).

Every time we tried to view the properties in the Exchange Administrator, we got a message indicating that replication had not yet completed. You get the following message:

The object canot be found in the directory.
This may be because replication has not completed.
Microsoft Exchange Directory ID no: c1010aae

It turns out that the folders we could not take control of had the "Limit Administrative Access to Home Site" property enabled. This is pretty common in most Exchange 5.5 organizations. The whole reason that feature exists in the first place is to keep someone from disconnecting their site from directory replication and taking ownership of all of the folders in the hierarchy. Trust me, it happens. :-0

These "orphaned" but unmanagable folders will automatically be cleaned up during online maintenance after they have been orphaned for 20 days after the removal of the Exchange 5.5 site in which the folder lived. Each Exchange 5.5 server will clean these up after the counter hits 20 days, so some patience is in order.

However, it is possible to speed this process up somewhat. In the following registry key, create a REG_DWORD value and set the data to 900 decimal (15 minutes):
HKLM\System\CurrentControlSet\Services\MSExchangeIS\ParametersPublic

Then wait for online maintenance to complete. If you have more than one Exchange 5.5 server with public folders, you will want to do this on each server. Do NOT run this if you suspect that you will be rejoining the site back to the organization again.