What to do if Steam client crashes
If Steam crashes shortly after it finishes loading, you can try one of the workarounds below.
(Note that nVidia PhysX is particularly nasty if a steamapp tries to install it by itself. If this has happened to your affected bottle, the workarounds listed here might not work.)
* Force Steam into an update by deleting 'ClientRegistry.blob' You can find this file in your bottle's C:\Program Files\Steam\ folder.
* Reinstall Steam into the same bottle