Outlook 2021 Contacts Window Opening in Fullscreen

I just want to add another bit of information. The other machine is running Windows 11 22H2 (OS Build 22621.521) and not Windows 10. I apologize for the confusion. So the two machines are running the same OS. The office version on each system is the same with the exception of the last 4 digits of the product ID which are slightly different. Why would they behave differently?

I am technical and I'm employed by a technical organization. So I have done my share of troubleshooting H/W as well as S/W. this is in case someone has a complex solution that needs to be implemented. To me, this issue sounds like an office issue which can be a setting or a behavior between OD and Office

Thanks in advance

Have you tried opening Outlook in safe mode, like MasterNeo suggests?

If Outlook behaves normally in safe mode but you can't figure out which add-in causes this issue, then perform a clean boot in Windows. A "clean boot" starts Windows with a minimal set of drivers and startup programs, so that you can determine whether a background program is interfering with your game or program.  This is similar to starting Windows in Safe Mode, but provides you more control over which services and programs run at startup to help you isolate the cause of a problem.  

Disclaimer: A clean boot is a means of troubleshooting, not a condition suitable for normal long-term use. Some applications may not be able to be used in this mode, please exit them after testing.

Hello, fellow members of the community, this is an update on the Outlook/Contacts issue. I have tried everyone's suggestions with partial luck as follows:

Note: It seems that at least one of you believes that I cannot start Outlook or that Outlook doe snot run. Outlook runs and the rest of its modules work just fine. It is only the Contacts module that seems to want to occupy the entire window and only shows one contact - the first one alphabetically listed. I have provided a screen capture of the screen in my previous post

I have done the following per your suggestions:

1. I ran outlook in safe mode. As I said above, Outlook starts. All modules work fine including the contacts. I see the two contacts that I created as a test. When I look at the Outlook "COM Add-ins", they are all in there. So what is happening in safe mode? What is been excluded that might be causing the issue?
2. I ran Outlook in normal mode and remove all the add-ins just for laughs. The contacts module did not work normally.
3. I followed Yuhao's advice to perform a "clean boot in windows" and all other steps. This did not fix the issue either. However, I notice that after I reboot the previously disabled services were all back in the list of "system config". The start up stuff was all disabled.
4. FYI! I have 3 systems running Win 11 2H22. Two have the contcts issue. The other works just normal. I checked the Outlook settings side by side, all 3 look exactly the same

I appreciate any help ypou can provide beacuse my next option will be to reset Win 11 2H22 and start fresh. I do not really want to do this if I can avoided

Thanks to you all!

I am running Windows 10 and have run into the same problem as you. I have been following and have tried my own work around. No success, but glad you are pursuing this problem. I will keep following this thread. Thanks.