I had an odd issue where SQL Server Management Studio (SSMS) 2008 R2 would start up, display the following error message, then exit:
Package ‘Microsoft SQL Management Studio Package’ failed to load
Using SysInternals Process Monitor tool to monitor SSMS.exe it seemed that it was looking for the following registry key but not finding it:
HKEY_CURRENT_USERSoftwareMicrosoftMicrosoft SQL Server100Tools
By renaming a parent key (rather than delete it – just in case it didn’t fix the issue) solved the issue for me. The key I renamed was:
HKEY_CURRENT_USERSoftwareMicrosoftMicrosoft SQL Server
Running SSMS again recreated the 100Tools sub keys and all was well again. I hope it works for you too.
Duncan Smart's Blog 
Worked for me. Thanks!
Worked, thanks!
Wow!
Thanks!)
thank you…3x…
THANK YOU!!!!
Hi
Thanks but no cigar. The key was recreated and launching SSMS stated it was setting up for first time use but then displayed the same error again. I guess it is reinstalling .net as the next possible cause.
Windows Server x64 with SQL Express.
Tony
This is exactly what it did for me as well. 😦
Me to 😦
I just now tried to run the ‘repair’ on .NET but this did not work. I am going to try running the ‘repair’ on SQLExpress next.
SQLExpress SSMS had been running great for two days after installation and then I started to get the ‘package’ error. I almost tried the SQL re-install repair when I noticed that SQL Service Pack 1 was waiting in the Windows update queue. I thought that all the updates had been applied already…
After finishing the service pack update SSMS opens up just fine.
Tanks Duncan
It works! Thanks!
Excellent – it worked for me!
Thank you very much! Nice job!
simply great!!! Worked.
Thanks a lot for an easy solution!
nop still i m getng same error.plz help me 4dis
waooooooooooooooooow !
excellent !
god bless you
@anu : rename the Microsoft SQL Server key
worked like a charm!
Thanks!
Legend!!! I have had issues on 2 machines now with VS 2010 and SSMS. I wish I had have found this before I started the laborious task of rebuilding the first machine…
Thanks a lot!!!
It was not working on my site. I suppose, I got a problem with .NET via Windows Update.
http://blogs.msdn.com/b/astebner/archive/2008/08/28/8904493.aspx worked for me.
Thanks, this worked for me.
Can you please provide steps how you did it exactly.
* Start > Run > regedit
* navigate to HKEY_CURRENT_USER\Software\Microsoft\Microsoft SQL Server
* right-click, Rename ‘Microsoft SQL Server’ folder/key
worked thx
Great! But don’t forget to restart your machine before running SQL again.
Thank you!
The only solution that worked for me!!!