If you change/copy the profile to point to a folder to which cannot be created, then the launcher fails to create the game directory as expected, but this locks the launcher into a launch limbo with only way to fix is by restarting.
Replicated by
Created launcher_profile.json on one machine with account name "Laptop"
Copied .minecraft folder to my new account named "Joshua"
Attempted to launch game without fixing path
Is this still a concern in the current Minecraft Launcher version 2.0.805 / 2.0.806? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases. If this has been done, we can reopen the issue.
Keep in mind that the "Resolved"-Status on this ticket just means "Answered", and that we are waiting for further information on whether this issue still exists or not. It will be reopened it as soon as the requested information has been delivered.