Before my computer started lagging with photoshop CC (see my other post Photoshop CC 2018 unusably slow, brush lagging, Windows 10 ), it had and still has a crash when I am trying to select things. This crash occurs both before the latest patch and after.
When I use any of the lasso tools to make a selection the program has a tendency to freeze if I click too quickly, and it never recovers. I've waited about 15 minutes and it remained frozen all that time. Not the computer, just photoshop. It's happened to me 6-8 times so far and always happens with the lasso tool/polygonal lasso tool which are what I use. Haven't tried the magnet.
I've learned to always save before using the lasso tool and expect it to crash. To recover I control+alt+delete and close the app.
It appears to have been due to my AMD graphics card using a very old version. Updating it seems to have solved the issue.