Outlook 2010 Cannot enable add-in in outlook 2010

Mark Foley

Senior Member
Outlook version
Outlook 2010 64 bit
Email Account
I have just downloaded and installed CalDavSynchronizer on Windows 7 and Outlook 2010. When I run Outlook, the CalDavSynchronize tab does not show. When I go to File > Options > Add-ins, I can see that this add-in is disabled. I then go to Manage COM Add-ins > Go, and I then check the box beside CalDavSynchronizer, then OK, but it does not enable. I've tried rebooting the computer, but that didn't help. I've deleted this add-on in Outlook, then uninstalled and reinstalled CalDavSynchronizer twice, Nada. The crazy thing is I've installed this add-in successfully on two other computers, one Windows 7 with Outlook 2010 and the other Windows 10 with Outlook 365. I don't get why this computer is giving me trouble. Note that "load behavior" on the 'Manage' screen says "Unloaded". All the other add-ins say, "Load at startup". The Location for CalDavSynchronizer has, "file:///C:\Program Files (x86)\CalDavSynchronizer\CalDavSynchronizer.vsto|vstolocal" which also seems odd. Other add-ins simply have "C:\program Files\..." or "C:\Program Files (x86)\..."

I must be doing something wrong. Ideas on how to fix this?