Outlook Troubleshooting First Aid – disabling add-ins
A lot of Outlook issues are caused by various add-ins. So, disabling all add-ins is a useful step and should be the first step for Outlook troubleshooting.
Please note every add-in will be a subkey under the following subkeys.
HKEY_LOCAL_MACHINESOFTWAREMicrosoftOfficeOutlookAddins
HKEY_CURRENT_USERSoftwareMicrosoftOfficeOutlookAddins
HKEY_LOCAL_MACHINESoftwareMicrosoftExchangeClientExtensions
HKEY_CURRENT_USERSoftwareMicrosoftExchangeClientExtensions
So, to disable all add-ins thoroughly, we can follow the steps below.
1. Click start -> Run… -> Type "regedit" (without quotation mark) and Click OK
2. Locate the following subkey
HKEY_LOCAL_MACHINESOFTWAREMicrosoftOfficeOutlookAddins
3. Backup and Delete all subkeys under above subkey
4. Repeat step 1-3 for the remain 3 subkeys
HKEY_CURRENT_USERSoftwareMicrosoftOfficeOutlookAddins
HKEY_LOCAL_MACHINESoftwareMicrosoftExchangeClientExtensions
HKEY_CURRENT_USERSoftwareMicrosoftExchangeClientExtensions
Now, all add-ins are disabled. If the issue disappears, it means the root cause is a conflict between Outlook and some add-in. We can restore the registry back and delete them one by one to find out which one cause the issue.