If you are getting this error message when opening:
The 'SqlSourceControlPackage' package did not load correctly.
The problem may have been caused by a configuration change or by the installation of another extension. You can get more information by examining the file:
This is caused by an incompatibility in having SSMS's object explorer on the right side of the screen.
This error can be resolved by moving the object explorer to the left and restarting SSMS