Thursday, October 27, 2011

Outlook Express can compact messages

Every time I reboot my work laptop, I get a message stating "To free up disk space, Outlook Express can compact messages." That's an interesting trick, because I don't even have OE installed on this machine.

At first I assumed it was something in the Run key of the registry, but a quick perusal of the HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Run key didn't show anything related to Microsoft Office, Outlook, or Outlook Express. I ran msconfig.exe and checked everything it said was loaded. No joy there either.

Finally, I turned to a Google search, and turned up this thread.

Basically, here's what's going on. When you install Windows Search, it has some default locations that it will index. Those include your "My Documents" folder, Outlook if you have it installed, and Outlook Express (apparently, even if it's NOT installed). But how does Windows Search indexing a non-existent installation of Outlook Express trigger a prompt to compact messages?

Well, each time OE starts or is accessed, it increments a counter that is stored in the registry. Once this counter goes above 100, it prompts the user to compact messages at the next reboot. If the user selects "Yes", the counter is reset. If they don't, it's not, and you get nagged each time.

So, the fix is a two-step process. First, we have to tell Windows Search to stop indexing Outlook Express. To do that, look in your System Tray (the spot at the right edge of your task bar with all those funny icons, next to the clock). There should be a magnifying glass icon down there (you might have to expand your systray to show hidden icons). Right-click on the magnifying glass, and then select Windows Search Options. In the Indexing Options dialog that comes up, you will most likely see two or three entries under "Included Locations". One of these will say something like "Microsoft Outlook Express: Main Identity". That's the culprit. Click the "Modify" button, and in the next dialog box, uncheck "Microsoft Outlook Express" and then click OK. Click "Close" to exit "Indexing Options".

Now, Windows Search will stop accessing Outlook Express, which will stop incrementing that counter. However, you will still get the "compact messages" prompt the next time you reboot. There are two ways to make the message go away. First, just click "Yes" the next time it comes up. Since you're not using Outlook Express, it won't have anything to do, but it will reset the counter back to zero. Alternatively, you can edit the registry entry yourself to reset the counter1. To reset the counter yourself, run 'regedit' and then go to the HKEY_CURRENT_USER\Identities key. Under there, you should see one entry that is called a GUID. It's a big long scary looking alpha-numeric value in between curly braces ({}). There should only be one entry under there. Expand that, and then drill down into Software\Microsoft\Outlook Express\5.0. In the 5.0 folder, you should see a key that says "Compact Check Count". Reset this to '0' (zero) and you're all done.

The next time you reboot, you shouldn't get that annoying message.

1Normal disclaimers apply. Intended for advanced users only. Back up your registry first. If you screw up your computer it's not my fault. If you're not comfortable doing it, take it to a professional.

P.S. - I'm still trying to figure out why the system does the Outlook Express Compact check if OE is not installed. My guess is that some Office service pack did a stealth or partial install of OE, because OE is nowhere to be found in my "Add/Remove Programs" dialog.


  1. Wow that was confusing. You do realize that if I have computer issues I just call you right? :)

  2. Yes yes, I know.

    The curse of being the family IT guy :)