Autocomplete not working

I have Microsoft 365 Version 2512: January 13, which is the latest update.

I am operating Windows 11 Home Version 25H2.

When I try to use the autocomplete facility in Excel it does not work. 

The 'Enable autocomplete for cell values' tick box & the one below in File; Options; Advanced are both ticked.

I have tried this in all existing worksheets and IMPORTANTLY in a new blank worksheet.

I have asked a friend to try it on his Windows 11 laptop with the same Excel and his does not work on his either.

HOWEVER, it does work on my MacBook which is operating system Monterey Ver 12.7.6 & Excel Version16.89, which is an older version.

There it works in both a new blank worksheet AND also if I copy the relevant file and paste into the Apple iOS system.

I have posted questions on Q&A but have not had any response that indicates a valid reason for the problem or more importantly how to solve it.

I would obviously like to speak to someone but I think this is likely to be impossible.

It appears that autocomplete does not function in Excel in Windows 11?

Can someone help?