Outlook error: “This operation has been cancelled due to restrictions in effect on this computer”

The default browser has been changed from IE to another application. and corrupt some registry entries.

Solution:

Close outlook and any web browsers you may have open.

Open an elevated command prompt window (run cmd as admin)

Type the following commands line by line into the command prompt window

REG ADD HKEY_CURRENT_USER\Software\Classes\.htm /ve /d htmlfile /f

REG ADD HKEY_CURRENT_USER\Software\Classes\.html /ve /d htmlfile /f

REG ADD HKEY_CURRENT_USER\Software\Classes\.shtml /ve /d htmlfile /f

REG ADD HKEY_CURRENT_USER\Software\Classes\.xht /ve /d htmlfile /f

REG ADD HKEY_CURRENT_USER\Software\Classes\.xhtml /ve /d htmlfile /f

Open Outlook and try again.