Open dialogs are not showing file extensions

[Peter Kinross]

Out of the blue Win 10 open dialogs are not showing file extensions.
Particularly frustrating when I want to open similarly named Access Dbs and have accdb, laccdb, ldb and mdb ones but no idea which is which. Well I can get a clue by file size and date of last modification, but still frustrating.
I have Explorer set to show file extensions and also hidden files.
Any ideas on how to get this option back?

[DaveA]

Have you tried to open File Manger (Windows Explorer), then the View tab.
There you should see the "Show/Hide" section of right center area of the ribbon bar.
You need a check mark in the box for 'File name extensions'

[Peter Kinross]

Thanks Dave. Yep that worked.
I use Directory Opus instead of Windows Explorer and had it set in that. First time EVER that Do hasn't worked - well it did work in Do, and that always carries through to Windows Explorer, but not this time. Guess I should have updated to the latest version of DO - I'm still using a 2 or 3 year old version. So not DO's fault. Directory Opus being one of the best and most loved programs on my PCs
The need for this is strange, as I had the option "Hide extension for known file types" un-ticked in Control Panel | File Explorer Options.
Thanks again Dave.