I am running Windows 10. I tried to open a solution in Visual Studio, and could not do so without upgrading that solution to .NET Framework 4.8. I don't want to do that, as it is a team project.

I tried to install 4.6.2, which is what it wanted, but could not - got the "a newer version is already installed). So, searching for a way to get it to install, I found a suggestion of uninstalling other .NET framework versions. I uninstalled 4.8 in the Windows Features, although it still seems to be there. I uninstalled 4.5.1 and 4.5.2 from Control Panel.

Now when I log into my computer, I am bombarded with errors that 4.0.30319 is missing, 4.5 is missing, and so forth. I tried going to Visual Studio Installer, to see if I could install them from there, but 4.5 is required by VS Installer. 4.0 will not install. 4.5.1 and 4.5.2 will install. 4.8 installed. But the software isn't detecting any of them.

I installed the 4.5.1 devpack. 4.5.2 devpack. 4.8 devpack. None of these have allowed me to run the VS installer. I can see 4.5.1 in the control panel, so it's there. 4.8 is checked in Windows features, so it is there. But the VS Installer tells me that it needs 4.5 and can't find it.

Does anyone have suggestions as to how to get my VS Installer at least working? From there, maybe I can try individual component versions. Even the VS Installer Setup application won't run, needing 4.5, and the same with attempting to uninstall the VS installer.

CodePudding user response：

Well, I've tried everything I can find online. Tried a .NET Framework Repair Tool (https://docs.microsoft.com/en-us/dotnet/framework/install/repair) which didn't repair anything. Tried installing older versions of VS hoping that they'd "properly" install the necessary .NET Frameworks, but the installs all hung (tried 2017, 2015, 2012, and 2010, since the frameworks that can't be found go back to 4.0.30319). Those were a flop. Can't tell you how many times I've uninstalled and reinstalled 4.8 and 4.5. 4.6 and 4.0 will not install because they say that there's a newer version (why doesn't 4.5 say that??).

Tried a Windows 10 startup repair, and that didn't find anything to repair.

So at this point I've got a ticket in with my IT department to reimage the PC. I've copied all my files to a network share and just waiting for them to come do the deed.

The lesson here is never, never, never, uninstall old versions of the .NET framework that are on your PC. Something is probably still using them.