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Windows 7 Ultimate RTM already comes with the .Net Framework 3.5 SP1 preinstalled. However, some installers like the Azure tools and SDK 1.1 seem to check for it and fail:

Windows Azure Tools for Microsoft Visual Studio requires .NET Framework 3.5 SP1.

Since the framework is preinstalled there seems to be no way to reinstall or repair it (see also).


  • VisualStudio 2008 SP (9.0.30729.1)
  • VisualStudio 2010 RC (previosly beta)
  • Windows\Microsoft.NET\Framework contains folders for all 1.0, 1.1, 2.0, 3.0, 3.5, 4.0

Any ideas on how to make the installers recognize the 3.5SP1 framework (without reinstalling the OS), or maybe to somehow reinstall it

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Paint.NET had the same issue. On their Roadmap page, for release 3.5.2, they say "Some Win7 systems could not detect that .NET 3.5 SP1 was installed, even though it was. A fallback detection function has been added". Not a solution, I know, but just to tell you're not the only one. – Snark Feb 9 '10 at 12:15
up vote 7 down vote accepted

As described here:

The promlem has been fixed after HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v3.5\SP was set to 1.

More info here too (linked in the page above):

Also could you check the following two registry keys and let me know what the values are?

HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\NET Framework Setup\NDP\v3.5\SP



To get pass the install error, if the value of the registry is 0, set it to 1.

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thanks for the fast answer – Christoph Rüegg Feb 9 '10 at 12:26

What solved the problem for me:

  1. Control Panel > Programs > Turn Windows features on or off
  2. Uninstall "Microsoft .NET Framework 3.5.1" (and child nodes)
  3. Install "Microsoft .NET framework 3.5.1" (and child nodes)
  4. Reboot
  5. Installers (at least the Azure ones) now recognize 3.5SP1 again
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