# Solved: Outlook and IMAP cached headers



## AndyBern (Jun 7, 2011)

When use Outlook to get my email, a short message appears saying it is updating cached headers. I have no problem with this, except it says there are over 11000 cached headers to update, and my IMAP folders only contains about 32 emails total.

Where are all these cached headers stored? In Outlook? On the server? Is there a way to clear them out?


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## AndyBern (Jun 7, 2011)

I solved the problem with the cached headers updates:

My IMAP store has about 300kb of message content. The local pst folder should contain no more than this.

I checked the folder size (right-click on IMAP folder, select Properties, then Folder Size) and it said something close to 200Mb. I tried the Compact Now button on the Properties/Advanced page but it didn't do a thing.

Looking at the folder properties, I got the pathname of the pst file that the IMAP folder uses. I exited Outlook, then manually renamed that pst file to something else.

Entering Outlook again gave an error since it couldn't find the pst file. However, Outlook automatically recreated it after exiting and restarting Outlook. (I don't know if the restart was necessary.)

After Outlook synchronized the new folder with the IMAP store, I saw a lot of old emails marked for deletion that I had deleted earlier. I purged them, and then checked the folder size. Now it's slightly over 100k. Much better... and no more "updating cached headers" messages!

All of those cached headers seem to have been located in the IMAP store, but weren't showing up in Outlook. Perhaps Outlook has not been purging messages from the IMAP store when told to? This is something to keep an eye on.


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