First off, please check that you are running the latest version of Photoshop 21.1.1(Check this under Help> System info)
Workaround if you're using 20.0.7 or earlier
In the Finder, launch System Preferences and navigate to Security & Privacy > Privacy tab > Full Disk Access. Click the lock icon in the lower left, enter your admin username & password. Click the + icon and add Photoshop to grant access to your hard disk.