I just updated to PS v 21.0.3 20200115.r.91 2020/01/15: 21f283574f6 x64. The latest version of PS does not recognize my scratch drive. That is, PS | Edit | Preferences | Scratch Drives does not list the scratch drive.
The prior version of PS used this scratch drive without issue.
The drive is
457 GB free
Users: Full control
Authenticated users: Full control
The computer has been restarted. I have deleted ...AppData\Roaming\Adobe\Adobe Photoshop 2020\Adobe Photoshop 2020 Settings.
This problem is not resolve and prevents me from using PS.