Outlook 2010 Crashes When Loading Add-Ins

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I just upgraded to Office 2010 Professional from Office 2007 Professional. I uninstalled Office 2007, rebooted, then installed Office 2010. I am using Windows 7 64 bit version and I installed the Office 2010 Professional 32 bit version.

I am getting a problem with when I start Outlook. When it is loading the add-in's the program is crashing. I ran it in safe mode and I identified the microsoft exchange add-in and a couple of others as causing the program to crash. I unchecked the boxes so it won't load on start up but this never happened with Outlook 2007. I ran setup and did a repair thinking that maybe a module didn't get installed correctly but that didn't solve the problem. I could uninstall then reinstall the program but it works fine without loading the add-ins in question.

My question is why are these add-ins giving me this problem? If I don't load them will Outlook still work okay? Why are add-ins needed for Outlook? Everything else works fine.



Roady [MVP]

Several add-ins will require an update in order to work correctly with Outlook 2010. The Microsoft Exchange Addin (UMOutlookAddin.dll) should not give you any issues as it is part of Outlook 2010.

Which are the other ones?

Add-ins are used to extend the default feature set of Outlook. Outlook itself comes shipped with several add-ins as well. Then there are loads of 3rd party add-ins to extend the feature set even more.


Did you install Office 2010 32bit or 64bit?

There some compatibility issue with add-ins in the Outlook 2010. May not work correctly.


I know the same thing happened to me on Word 2010 with the Endnote Add-In. I'm not sure why, but it seems that the Office 2010 applications can't handle all of these apps.


I disagree with the general statement that " The Microsoft Exchange Addin (UMOutlookAddin.dll) should not give you any issues as it is part of Outlook 2010." I disable this addin and my problem stops. Actually I don't see any loss of functionality but I've not looked very closely yet.

My situation - I have office 2010 installed on Windows 7 pro 32 bit. All was fine until I installed Windows Live Messenger Beta. When I attempt to change an occurrence of series appointment in my calendar I get a 'One or More parameters is not valid' message. The evening before I had opened and tried OneNote as well. I de-installed OneNote, and that didn't fix the problem. Google tells me that there are tons of Outlook startup tasks like /resetfolders etc... but I don't think that is necessary yet. I started Outlook in Safe Mode and my machine worked. I enabled all the addins one at a time and the UMOutlookAddin.dll was the one that made the problem occur.

Now that said, The Live Messenger Beta is all about hooking social networking (facebook etc) to your Live Messenger and through that too your Calendar and contacts. I think the relationship is obvious. I intend to remove Messenger first, and research this avenue. There is so little info on UmOutlookAddin and what it does and is for that I landed here. I hope this helps other go forward.


Jim Shimota


I'm having the same problem. Outlook 2010 loads the add ins until it gets to the microsoft exchange add in and then it loads continuously and never opens. I can open it in safe mode.

Where and how did you uncheck the ms exchange add in to not load?
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