Aaron Stebner's WebLog

Thoughts about setup and deployment issues, WiX, XNA, the .NET Framework and Visual Studio

Mailbag: Do I need still need older versions of the .NET Framework on my system after installing .NET Framework 3.5 SP1?

Mailbag: Do I need still need older versions of the .NET Framework on my system after installing .NET Framework 3.5 SP1?

Rate This
  • Comments 44


I recently installed the .NET Framework 3.5 SP1 on my system.  Afterwards, I looked in Add/Remove Programs, and it shows that I have all of the following versions of the .NET Framework installed on my system:

  • Microsoft .NET Framework 1.0
  • Microsoft .NET Framework 1.1
  • Microsoft .NET Framework 2.0 SP2
  • Microsoft .NET Framework 3.0 SP2
  • Microsoft .NET Framework 3.5 SP1

Do I need any of these older versions of the .NET Framework now that I’ve installed the .NET Framework 3.5 SP1, or can I safely uninstall them?


When you install the .NET Framework 3.5 SP1, it will also install the .NET Framework 2.0 SP2 and the .NET Framework 3.0 SP2 behind the scenes.  You cannot use the .NET Framework 3.5 SP1 unless you also have the .NET Framework 2.0 SP2 and 3.0 SP2 installed.  Therefore, you will not be allowed to uninstall the .NET Framework 2.0 SP2 or 3.0 SP2 if you have the .NET Framework 3.5 SP1 installed.  If you try to uninstall those versions of the .NET Framework, their uninstall processes will block and tell you that they are needed by another application on your system.

The .NET Framework 1.0 and .NET Framework 1.1 can be installed side-by-side with the .NET Framework 2.0, 3.0 and 3.5.  Most applications that were created for the .NET Framework 1.0 or 1.1 will automatically use the .NET Framework 2.0 instead if it is installed on the system.  In most cases, that means you do not need to keep the .NET Framework 1.0 or 1.1 installed on your system if you already have the .NET Framework 2.0 installed.

However, there are some applications that are configured to require a specific version of the .NET Framework, even if later versions of the .NET Framework are installed.  If you have any applications like that on your system and try to run them without installing the .NET Framework 1.0 or 1.1, you will get an error message that looks like the following:

MyApplication.exe - .NET Framework Initialization Error
To run this application, you first must install one of the following versions of the .NET Framework:
Contact your application publisher for instructions about obtaining the appropriate version of the .NET Framework.

In the above error message, the version number will be v1.0.3705 if you need to install the .NET Framework 1.0, and it will be v1.1.4322 if you need to install the .NET Framework 1.1.

If you end up seeing any error messages like this, you can re-install the .NET Framework 1.0 or 1.1 in order to resolve the errors.  If you don't end up seeing any error messages like this, then you don't need to worry about re-installing the .NET Framework 1.0 or 1.1.

  • PingBack from http://blog.cwa.me.uk/2009/04/21/the-morning-brew-331/

  • De afgelopen periode was nogal een periode van veranderingen. Zo was er de bijna overname van Sun door

  • PingBack from http://www.keyongtech.com/5162625-net-framework-question

  • Many thanks Mr Stebner!  All the heartache and frustration of MS is assauged by all the kind folks like you who offer so much great help out of the kindness of your hearts!

    Peace and Blessings! from Belly-view

  • Thank u for the answer, to the point and informative!

  • Do I need the .NET Framework 3.5 SP1 now that I’ve installed the .NET Framework 4?

    Or can I safely uninstall .NET Framework 3.5 SP1 after I've installed the .NET Framework 4?

    Thank you.

  • Hi Leo - By default, the .NET Framework 4 does not allow all applications built for earlier verisons of the .NET Framework to migrate forward and run on it if the earlier versions are not installed.  If you are using any applications that were built with any version of the .NET Framework before version 4, then I would recommend leaving both the .NET Framework 3.5 SP1 and 4 installed.

  • Thanks for the info. That's what I suspect too.

  • Does the same apply to XNA framework versions?

  • Hi Phespy - No, this guidance doesn't apply to the XNA Framework.  Each version of the XNA Framework is completely side-by-side and does not know about any other versions.  You must make sure that you deploy the exact version of the XNA Framework that your game is built against, even if any other versions of the XNA Framework are already installed on the computer.

  • Thank you very much for the help and quick response

  • Thank you for your response, it answered my question on Net Framework.

  • The .net framework is taking all my memory :/ ... (yes, it's an older beater laptop with a C and D drive with 19 & 17 GB.  Anyone heard if they are coming out with a newer version or something that can replace all those memory hogs??? Love to delete 1, 1.1, 3.5, 4.0 etc. tired of that little icon at the botton saying almost out of memory space. Thanks for your comments

  • Hi Shawnee - Each version of the .NET Framework is designed to install and run side-by-side with older versions, so there won't be a new version that replaces all of the previous ones.  That being said, most older .NET applications will run correctly if you have 3.5 installed and you can probably uninstall the .NET Framework 1.0 and 1.1 from your computer if you are low on disk space.

  • Ugh... hope they modify that someday... thanks for the advice... I'll give it a try. Merry Xmas :) S.

Page 1 of 3 (44 items) 123
Leave a Comment
  • Please add 3 and 2 and type the answer here:
  • Post