The SQL Server 2005 Express Tools are installed. To continue, remove the SQL Server 2005 Express Tools. If you are getting the above error while installing Sql Server Management Studio 2008 then probably you might try the below given solutions one by one to fix this error. I m not certain what will work for you but i have added all the options which i found after spending some time on the net which various people have given and for me the most common one worked which also i have listed below.

  1. Rename the key “HKLMSOFTWAREMicrosoftMicrosoft SQL Server90”. This worked for me i renamed the whole folder to “old” and then the installation started passing all the test. For x64 Windows Server 2008, the reg key needed is: “HKLMSOFTWAREWow6432NodeMicrosoftMicrosoft SQL Server90” ( Thanks to adam).

Once Sql server Management Studio is installed successfully, then restart your system sql server installation will automatically ask you for a restart. After restarting you will see that your sql server 2005 instance will stop working because you played with the 90 directory and if you try to rename old to 90 then the system will not allow you to do so as it already created an entry name 90 for you having “Tools” and “Shell”. So now we are in deep trouble what to do next, what i did was i again renamed the 90 entry which it created to 70 and the entry for sql server 2005 which we renamed as old, again back to 90 and voila everything works fine now. Both sql server installations are running side by side and both management studios are also running side by side anyways we can open old database in SSMS 2008 so there is no need to have SSMS 2005 unless and until there is some special requirement. This was the hit and trial method and it worked for me for the first time but i would not suggest this method to be done on any full fledged install although you may test this on your virtual pc or vmware installation as it might corrupt your sql server 2005 installation in some cases. 2.Try uninstalling any redgate products if you have installed any especially Red Gate Sql Prompt, this also caused issues to some users. 3.Try uninstalling sql server Management Studio 2005 before installing SSMS 2008 Above listed three ways will do the task for you, if you have resolved the problem in some other easy and concrete way then please do post your comment. Happy Programming!!!!!!!!!!!!!!