Windows security: By default, Controlled Folder Access protects common folders such as Documents, Pictures, Videos, Music, and Desktop. You can also add additional folders to be protected. You have to go to Windows Security/ Virus and Threat protection/ Manage settings/ manage controlled folder access/ Allow an app through controlled folder settings/ add an allowed app. (Tilt Brush, Open Brush, Steam) etc. If that doesn't work, there are more aggressive actions that can be taken involving the command line etc. you can google that.