1 ) It could be that some previously opened blend file’s saved settings are affecting your Blender globally. In which case you might try enabling the Load UI User Preferences setting to force Blender to use individual settings per blend.
2 ) You might also try resetting/restoring globally your Blender’s default setting with Load Factory Settings. If you don’t save a blend, the default settings won’t be restored, allowing you to experiment with default settings without any of them saving. You can even run Blender with the factory startup commandline script that should be in your root Blender folder.
