This issue can accrued after outlook upgrade or changes in default browser, few ways to resolve this :
Download this easy fix from microsoft here and just install it or Local download : MicrosoftEasyFix50388
You can also check registery for the right vaues:
open regekey :
HKEY_LOCAL_MACHINE\Software\Classes\htmlfile\shell\open\command
Make sure you have default browser value, For example : “C:\Program Files\Internet Explorer\IEXPLORE.EXE” %1
Verify that the String (Default) value of the “HKEY_CLASSES_ROOT \.html” key is “htmlfile”
More information can be found here
Hi,
I have the same problem using Outlook 2013 and I used your solution. After some days the problem occurred again. The registry entry missing! Easy to solve but annoying. Some cleaning app deletes the entry!
Will upgrading to Outlook 2021 solve the problem?
I think it will solve your problem