We're sorry about the trouble with Photoshop. Would you mind telling us what happens when you try to use Save for Web in Photoshop? Are you getting an error?
You can go to the System Preferences for your Mac, then Security and Privacy, then select the Privacy tab. Then select Accessibility from the list to the left & check if Photoshop is added to the list with a check mark in front of it. If Photoshop is not a part of the list, please add it by unlocking the window first using the lock at the bottom left, then clicking the + icon & navigating to the Applications folder. Also, grant permissions to Photoshop under Full disk access located in the same list as Accessibility. Once done, restart the Mac & check if it helps.
Good news for you! I discovered a fix. If you uninstall Photoshop 2021 and reinstall the latest version of 2020, you’ll find that 2020 works fine. Now go ahead and install photoshop 2021 but leave photoshop 2020 installed as well. Now verify that the 2021 version is working as expected. If so, you can now uninstall Photoshop 2020 and leave 2021 and everything will be working fine.
It’s crazy that we have to do this but it does fix it.
I get this error; "could not complete this operation. a write permissions error has occurred".
I have added Photoshop to all security and privacy permissions; Accessiblity, Full Disk Access, Files and Folders. Reset Photoshop preferences, performed a system reboot and it still doesn't work. However as I mentioned, with a reinstall Photoshop 2020 everything works as expected with no errors.