SQL Server 2008 setup Error - Microsoft .NET Framework 3.5 installation has failed. I know i have it installed already!

I recently worked with a customer who ran into an interesting situation. The issue deals with SQL Server 2008 RTM setup.

He is trying to install SQL Server 2008 Enterprise on a Windows 2008 x64 box. As soon as we click ‘setup.exe’, we get below pop-up.

When we check from Control Panel –> Add/Remove Programs, I can clearly see Microsoft .NET Framework 3.5 SP1 installed.

Then why this error?

Started with the few basic check of looking into Setup Bootstrap logs, but there were none!!! means setup error has not even logged.

The came an interesting revelation: Customer informed that he was able to successfully install SQL Server 2008 32 bit, on different box, using same installer.

This gave me a clue to take a closer look at the SQL Installer. I started looking into x64 folder, comparing them to our own SQL installer library. And, my suspicions were validated as I could find several file/folders missing within x64 folder.

Very next thing I did was to list the missing folders, rename then at my end and then try simulating the error (In Microsoft Support, we love to re-produce the issue and find a solution for it) and I could get the same error, whoa! So this is a case of SQL media corruption.

Resolution then become simple as we just replaced the corrupt media with fresh one and then customer was able to install SQL Server 2008 successfully.

Thanks for reading!

Disclaimer: I work at Microsoft. Everything here, though, is my personal opinion and is not read or approved by Microsoft before it is posted. No warranties or other guarantees will be offered as to the quality of the opinions or anything else offered here.