I just spent 30 minutes on SSMS which hanged on me every time I tried to launch it. I searched the Internet but couldn’t find a solution. The SMSS process was heavily using the CPU and slowing down the machine, but after the splash screen the SSMS application window wouldn’t appear.
Then I downloaded Process Monitor, saw that the process was continuously using a file called C:\Users\username\AppData\Local\Microsoft\SQL Server Management Studio\11.0\1033\Ssms.CTM.
I killed the SSMS process, renamed the Ssms.CTM file, and launched SSMS again. Problem solved!
In the comments section, plectoBne provided an alternative - and probably better - way to solve this issue. His suggestion is to rename
[HKEY_CURRENT_USER\Software\Microsoft\SQL Server Management Studio] (this is a registry key which you can edit with RegEdit.exe)
c:\Users\<profilename>\AppData\Local\Microsoft\SQL Server Management Studio\
and let SSMS create a new Environment
Thanks plectoBne for sharing!