I use CryptoPrevent and haven't noticed any issues. But I'm not a great one for clicking on file attachments from unknown sources anyway. Note the free version of CryptoPrevent doesn't autoupdate, so you need to check for updates from time to time.
Also, it simply installs a set of group policies, so it's run once to install the policies, and run again if you choose to delete them at some point: it doesn't run each time the computer starts. Basically, it stops unexpected and/or masked file types running in unexpected locations.
FOM.