In Photoshop CC 2018, released October 2017, When I tried to use the Select and Mask Tool, after making a selection, I get Could not apply the Workspace because of a program error. I have to install the last know version (2017) to continue working or to select & mask.
Hi Web_Zest,
I would suggest you to please update the Photoshop version to 19.0.1 update and check if that helps to fix this issue.
Photoshop CC 19.0.1 now available | Photoshop Family Customer Community
Regards,
Mohit