Using classic Outlook for Windows in business environments
I had a problem: I much prefer Classic Outlook but it kept being replaced by New Outlook on my Windows 11 pc and laptop. I engaged with Microsoft Support who provided five 'solutions' which didn't work.
In frustration I started investigating every aspect of Classic Outlook, and I've found a solution which works on both my devices - and it's so simple I'm amazed it's not been mentioned anywhere I've looked /searched before. (I don't have Windows 10 on any devices, but I presume it would work there just as well.)
Forget Powershell, Regit, olk.exe, and all the other Techy replies.
Try this:
Step1: Open Classic Outlook, then go to Start/Settings/Apps and uninstall New Outlook which will have loaded automatically when you opened Classic Outlook.
Step 2: Return to your opened Classic Outlook and go to File (top left of screen)/Options (bottom of left panel)/General
Step 3: Slide down to the very bottom of the General panel, and you should see a check box and the legend 'Automatically switch me to New Outlook'. Uncheck the box, close Options and return to the main Classic Outlook main screen.
Step 4: Close Classic Outlook and re-open it, then carry out Step 1 again. You should find that New Outlook hasn't been automatically re-installed.
Since I did all this I have had no problems at all with New Outlook re-installing or interfering with my use of Classic Outlook. I hope it works for you too.