Repeating 623 version store error.

Applies to Exchange 2003

I had a case a couple weeks ago I thought I’d write about.  What was happening is the Version Store would run out of memory and a 623 error would throw.  Version Store buckets allocated would climb from 4 to over 2000 in less than 5 minutes.  The store would then rollback its transactions for a bit, recover, run for 10-15 minutes and repeat the whole cycle over.

This is atypical 623 behavior to say the least.

What we ended up doing to fix it was capture an adplus dump, 3 actually, triggered at Version Store buckets allocated crossing 1600.  We captured 3 dumps at 1 minute intervals.

The 1st dump caught the problem transaction, the last 2 were both capturing rollbacks, so this was a quick ramp up.

Turns out the problem was being caused by a bad meeting request being processed over and over again.  We tried all kinds of ways to delete the message, all of which caused Version Store buckets allocated to climb.  A MFCMapi hard delete ended up doing the trick.

How to determine who is connecting to your server in cached mode.

Applies to:  Exchange 2000/2003


This may seem like a basic thing to some people, but for those who don’t know, here goes.  This can be easily done by running Exmon, available here.

So download Exmon and fire it up on your Exchange Server.

Go to the By Clientmon tab, and in there you’ll see a column named “Cached Mode Sessions”.  If you have something other than 0 in that field, then your user is connecting over Cached mode.


Hope that helps, I’ve had the question a few times before.