Platform Builder 10.5.2 has a number of fixes. Most importantly, a system has been added to help restore missing games automatically. Some have reported this problem, and so here I am at 1 a.m. with my fingers crossed that this will fix the problem. I suspect this issue originated with the Steam Cloud feature that was never meant to be activated for Platform Builder. I don't know how it switched on because nothing was configured properly, but I turned it back off. 10.5.2 -Added a function to help restore missing game files automatically. -Built-in star items now use the levitate setting. -Added a volume control for imported music (technically, we already had it, but it was not visible for a while). -Fixed: The manager button appears when defeat settings for custom enemies is set to "Do: Nothing." -Fixed: The assistant is not visible when speaking in Game Setup. -Fixed: Right-clicking on edit button in the workstation doesn't work if the button is disabled. -Fixed: The "select" button in enemy settings does not work for when the enemy defeat settings is set to "New Area". -Fixed: The wood tile set displays the wrong text in the workstation when it is selected. -Fixed: The wrong message appears when you are asked to start a new project in simple or advanced mode. -Fixed: Delay physic setting for custom projectile does not save correctly.