I'm running Outlook 2010 in Cached Exchange mode against an Exchange 2007 server. Outlook's status bar shows "updating cached messages (2/1950)" and the number never increments.

What does "updating cached messages" mean? Information is sparse.

Intuitively it seems like some kind of indexing process on the emails cached in the local .OST file.


It has to do with storing a local copy of the data residing on the Exchange server on your machine and referencing the Exchange server when a connection becomes present.

This allows you to continue operating locally and once a connection to the Exchange server surfaces the cached data can then get propagated to the Exchange server.

The fact that it is hanging could be any number of things

  • I definitely understand what Cached Exchange Mode is for and what it does but I wanted to specifically understand the "updated cached messages" part of things. Note that regardless of that message all mail is available to me offline via my .OST almost immediately after I create or receive email, so in that sense Cached Exchange Mode is working and storing that local copy, but seems something else is going on with that message. – Matt Feb 17 '11 at 16:27
  • @Matt Are you asking why is it hanging or what is it doing during the process of updating the cached messages? What it's doing is a component of the cached exchange mode being active. How granular of an answer are you looking for? – Aaron McIver Feb 17 '11 at 16:30
  • I might have put 2+2 together here now. Obviously CEM is partially working since all my emails are available offline but apparently it's not completely working as I can see in my problem. So the "updating cached messages" message is apparently a process that must complete successfully in order for these problems to be resolved. – Matt Feb 17 '11 at 17:24

With weird outlook things in cached mode, the easiest first step is to either scan the OST file, or just delete it.

In program files\office14, run the scanPST to scan your OST file. it will report if there is any corruption or errors.

Alternatively, since its cached, your Exchange server is the "master copy".. Just close outlook, (and communicator if you use it as well) delete the OST file, then re-open. it will create a new OST file, and rebuild the cache.

  • I'm going to try your first suggestion. I did your second suggestion and deleted the OST and let it recreate and repopulate. My problem instantly returned. Now I'm going to do the scan. – Matt Feb 19 '11 at 21:18
  • Nuts, did a scanPST, it did find some issues, still same problem. I'm going to try plan C, whatever that is. – Matt Feb 28 '11 at 4:06

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