Value cannot be null

After issues with my laptop not being able to find critical files this morning I managed to boot to the last know good configuration. This seemed to have got me past all the errors I previously had, however, I noticed that things weren’t quite right.
When attempting to open SQL Server Management Studio (SSMS) 2012 I received the error “Value cannot be null.” – this appeared when first connecting and then when expanding any of the nodes underneath the database server.
Also missing were the Local Server Groups and Central Management Servers child nodes in the Registered Servers panel.

 
Red Herring
On one Microsoft forum I found a proposed answer from a Microsoft employee who said they had been able to replicate the error and the fix was to repair the .NET 4 framework. I tried this and it made no difference whatsoever – it may work for you, please feel free to leave a comment if you had any luck with this.
Fixing the error
I found a workaround for this which is to right click the SSMS shortcut and “Run as Administrator”. This did seem to work but wasn’t a proper fix so I continued researching.
The fix comes in the form of Environmental Variables, setting the User variable TEMP and the System variable TMP to the appropriate locations (C:\users\<user.name>\AppData\Local\Temp) worked for me, I was then able to open SSMS fine with no errors.