-In order to rule out any plugin conflict would you please check whether any additional plugins are enabled in Outlook - if so, disable (temporarily) all other add-ins except harmon.ie To disable Outlook add-ins
• Go under File -> Options -> Add-ins -> Manage COM Add-ins and click Go...
• Deselect all add-ins except harmon.ie and click OK.
Restart Outlook - and go back under File -> Options -> Add-ins to verify that harmon.ie is the only add-in listed in the Active application add-ins section.
Then please run the following recovery procedure:
-Please stop Outlook.
-Uninstall harmon.ie from control panel, program feature
-Delete all dirs. C:\Users[user_name]\AppData\Local\Microsoft_Corporation\harmony_Path_pzllr20oqrnqmrstb3lfbn4njpshdzry (path can slightly change)
-Delete C:\Users[user_name]\AppData\Local\Mainsoft and C:\Users[user_name]\AppData\Roaming\Mainsoft
-Register the attached clean_Mainsoft_Reg_New reg file. at ftp://free:free@ftpus.mainsoft.com/Clean%20Mainsoft%20Reg_New.reg.zip (please use this one)
-Register the PreferredCLRversion registry key at ftp://free:free@ftpus.mainsoft.com/PreferredCLRVersion4.0.zip (please use this one)
-Reinstall harmon.ie. Please install our latest 5.3.1 from our web site.
-Start Outlook