Windows 10: Error when trying to install .NET Framework 3.5

A few days ago, I noticed I couldn't run some applications because of .NET Framework 3.5 not being installed on my system.I downloaded the installer from https://www.microsoft.com/en-US/download/details.aspx?id=21 but when I tried to run the installer,It said this:I tried pressing 'Tell me how to solve the problem' but the error wasn't present there. I also tried to find information of the error code using slui.exe but it said it could not find any information from it. Optional features also doesn't work because it doesn't list a single feature:mscoree.dll is also missing which means I ca

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Error when trying to enable .net framework 3..5

Hello,

Try enabling .NET Framework 3.5 using DISM:

How to enable .NET Framework 3.5 in Windows 11

Let us know if this helps!

Note: Included link in this reply refers to blog post by a trusted Microsoft MVP.

 

Unable to download any framework for .net - (error code 0x80070002)

OK, the Windows 10 Feature installation method should have been straightforward, but since that errored out as well, something else seems to be going on with your Windows, so wait for somebody with more experience to suggest a way out.

In the mean time, if you haven't already, you could give muchomurka's suggestion a go as well with the elevated prompt and an install media to see if it works. The following link shows the detailed steps involved.

Offline install of .NET Framework 3.5 in Windows 10 using DISM

 

Install .NET 3.5 Framework on Windows 10

Is it even possible, the help for this is of no use.

.NET Framework 3.5 installation errors - Windows Client | Microsoft Learn

This is the bit thats applicable to me.

To fix the error codes for Windows 10, follow these steps:

1. Download the Windows Media Creation tool, and create an ISO image locally, or create an image for the version of Windows that you have installed.
   
2. Configure the Group Policy as in Method 2, but also follow these steps:
   1. Mount the ISO image that's created in step 1.
   2. Point the "Alternate source file path" to the ISO sources\sxs folder from the ISO.
   3. Run the gpupdate /force command.
   4. Add the .Net framework feature.

Method 2 isn't mentioned anywhere.

Further more if i download the framework installer and run the dotnetfx35setup.exe file i get a window that says it requires the framework its trying to install, so its a loop that requires the framework to install the framework.

Next issue is that if i try to turn it on from Programs and Features in the control panel it throws me back to the initial error of not being able to install it which takes me back to the link above and method for fixing it which doesn't include the information
for Method 2.

I'm starting to think MS are purposely making it uninstallable at this point.

Any help would be much apreciated.