3.5.1 and 4.6.1 RRS feed

  • Question

  • My computer has both Microsoft .NET 3.5.1 and 4.6.1 on Windows 7. Should I remove one of these or leave both on?
    Thursday, August 4, 2016 9:17 PM


  • Hi Glad54,

    Welcome to the MSDN forum.

    The .NET Framework 3.5.1 can work side by side with the .NET Framework 4.6.1, please see the following description.

    Each version of the .NET Framework contains the common language runtime (CLR), the base class libraries, and other managed libraries. Each new version of the .NET Framework retains features from the previous versions and adds new features. The CLR is identified by its own version number. The .NET Framework version number is incremented at each release, although the CLR version is not always incremented. For example, the .NET Framework 4, 4.5, and later releases include CLR 4, but the .NET Framework 2.0, 3.0, and 3.5 include CLR 2.0. (There was no version 3 of the CLR.)

    So the .NET Framework 4.0 (or later versions) runs side by side with versions 1.1, 2.0, and 3.5, since they used the different versions of the CLR (2.0, 4).

    For the .NET Framework 4.5 or later versions, they are an in-plate update that replaces the .NET Framework 4, which means that they use the same runtime version, but the assembly versions are updated and include new types and members, you can keep both of them per your requirement.

    The .NET Framework versions 2.0, 3.0, and 3.5 are built with the same version of the CLR (CLR 2.0). These versions represent successive layers of a single installation. Each version is built incrementally on top of the earlier versions. It is not possible to run versions 2.0, 3.0, and 3.5 side by side on a computer.

    For more detail information about the .NET Framework Versions and Dependencies, please see here:

    Best regards,


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    Friday, August 5, 2016 5:30 AM