Camera Raw Filter won't open

SYSTEM:  Photoshop 20.1 on Win10 (ver 19041) desktop

PROBLEM: From Photoshop,  Camera Raw Filter won't open due to a program error.  Also ACR does not display in Bridge filters.

TRIED:

• Went to this page: https://helpx.adobe.com/camera-raw/kb/camera-raw-plug-in-installer.html
• Downloaded & installed ACR 12.4. 
• No joy.
• Reinstalled ACR 12.2.1.
• Still no joy.
• CC Desktop app says Camera Raw is up to date.

Any advice on what I should I try next?