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Thank you for the details. I completely understand how frustrating it is when emails won’t open the way you expect.
To give the best advice, may I know a few more details:
1.When you have “Popout only” selected, what exactly happens when you double-click a message? Does nothing happen at all or do you get any error message?
2.Please make sure your Outlook is the latest version
In the meantime, please try the very first basic step:
1.Quick Online Repair
-Close Outlook completely
-Go to Windows Settings > Apps > Installed apps
-Search for Outlook
-Click the three dots > Advanced options > Repair > choose Online Repair
-Once it finishes, open Outlook again and test “Popout only” + double-click
2.Reset the Outlook app
-Windows Settings > Apps > Installed apps > Outlook > Advanced options
-Scroll down > click Reset
-Sign in again and test
3.Completely uninstall and reinstall Outlook
-Windows Settings > Apps > Installed apps > Outlook three dots > Uninstall
-Reinstall Outlook and test
The initial response may not fully address your needs, please give these a try and let us know how it goes and we will investigate further
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