Resolving “OLMAPI32.dll is incompatible” Error When Upgrading from Outlook 2007 to Outlook 2010

outlook 2010 splash screenYou cannot/should not, it appears, retain Outlook 2007 installed on your PC after upgrading to Outlook 2010.

If, as I did, you do not de-install Outlook 2007 after the upgrade you may find that you cannot run Outlook 2010. In such case you may get the following error message when attempting to run it:

“The file OLMAPI32.dll is incompatible with Microsoft Outlook. Install Outlook again”

It may be possible that had I uninstalled Outlook 2007 or had I never attempted to run Outlook 2007 after upgrading to Outlook 2010, this error may never have appeared. Nonetheless, once this error appeared I was not able to run Outlook 2010 again until I uninstalled Outlook 2007 as described below.

Note: As always, before proceeding, I recommend creating a restore point in case something goes wrong.

According to this Microsoft Answers post, the solution did not lie in ”Installing Outlook again’ as the error message suggested. Rather, the solution required uninstalling Outlook 2007 and repairing Outlook 2010.

So, off to Add-Remove Programs from the Control Panel to Remove Outlook 2007 right? Not so easy.

You can’t directly uninstall any given Office 2007 application installed on your computer. They do not appear as individually installed items in the Add-remove programs panel. As described in this Microsoft knowledge base article (unfortunately written for XP and Vista users), in order to remove just one application from the Office suite in Windows 7, you need to ‘Change’ the features/applications installed in the Office 2007 suite.

To do this is Windows 7 you need to:

  • Go to Control Panel
  • Select “Uninstall a program” under the “Programs” heading
  • As depicted below, right click on the “Microsoft Office Standard 2007 item in the resulting “Uninstall or change a program” window and select the ‘Change’ option:

graphic depicting how to uninstall an application from the microsoft office suite

From there you’ll get the option to ‘Add or Remove’ Features’:

change your installation of microsoft office standard 2007

Click the radio button beside ‘Add or Remove Features” then click Continue.

As depicted below, X out the “Microsoft Office Outlook” application by clicking on the down arrow and selecting the ‘Not Available” option. Once X’d out, click on the Continue button:

customize which microsoft office programs are installed 

From there you’ll see this Configuration Process screen:

graphic depicting microsoft office standard 2007 configuration process

Followed by this success screen:

graphic depicting success at reconfiguring microsoft office 2007

After which, Outlook 2007 will be removed from your PC.

Reboot your PC.

Now run your previously installed Outlook 2010 and, if all has gone according to plan, you’ll see this Office 2010 repair screen instead of the OLMAPI32.dll error message:

 graphic depicting microsoft office 2010 configuring itself after fix

When done the following warning screen came up:

graphic that appears after fixing office 2010 OLMAPI32.dll error fix

Since I hadn’t seen this error message multiple times I selected ‘No”

From then on, My Outlook 2010 has run just fine.

May 29, 2009 Update: Well, things didn’t run so fine after that. I had the problem where Outlook 2010 couldn’t reliably connect to the Google Apps Gmail iMap server. So I went and ‘repaired’ my Office 2010 installation as follows:

  • Proceed again to the “Uninstall or change a program” window (see first image above)
  • Right click on “Microsoft Office 2010” in the list
  • Select “Change” (as you can see that I did in the picture above for Office 2007)
  • Select the ‘Repair” option as pictured below then press “Continue”


This will be followed by a ‘Configuration Process” notification screen.


When done, Office 2010 should be repaired.

So far, Outlook 2010 seems to be running without the errors I had before. I’ll update this post if more problems crop up. If there are no more edits, you can assume things are working fine again. Well, subject to known Outlook 2010 / iMap glitches that is. 🙂



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