Installer error: "The file has been downloaded incorrectly!"

When you open the installer, use everything to find the temporary folder whose first six letters are "gentee". When you find the folder, click next. If downloading repository.txt is failed, download repository.txt manually from sourceforge.net. If succeeded, choose the version you want to download, and download the package from sourceforge.net. Then put the package into the temporary folder whose first letter is "gentee". Then go back to the installer, choose where you want to install and click "Next".
Hope this can help you.
My home tougue is not English, try your best to understand.

Do not forget to look for what you want to ask before you ask.
Here: https://sourceforge.net/p/mingw-w64/support-requests/125/

I too am having the same problem but on Windows 10. The repository.txt file is downloaded correctly, so I can choose a specific setup. When I make my selections however, say "7.3.0, x86_x64, win32, seh, 0", click Next, then Next again, I get the "The file has been downloaded incorrectly!" error dialog. Disabling virus protection, firewall, etc. has no affect.

If I manually copy the http string from repository.txt, e.g.,

http://sourceforge.net/projects/mingw-w64/files/Toolchains%20targetting%20Win64/Personal%20Builds/mingw-builds/7.3.0/threads-win32/seh/x86_64-7.3.0-release-win32-seh-rt_v5-rev0.7z

then paste it into a browser, the .7z does start to download so that address appears valid.

Of course, I can install it manually. But the installer does more than download and really makes using Mingw64 a lot easier.

Perhaps I'm a bit of a dimwit here but I'm totally unclear as to how the work around with the gentee temporary file and the repository.txt file works. Neither of which appear to be downloaded to my Win 10 laptop. Unclear why numerous iterations of the correct setup settings fail to work.

If you don't see the folder or file, my guess is that your firewall/anti-virus is blocking the file from being downloaded. You could probably try turning it off to see. Or you just go to

https://sourceforge.net/projects/mingw-w64/files/Toolchains%20targetting%20Win64/Personal%20Builds/mingw-builds/

in a browser. All the various builds are listed there.

Okay, for anyone in the future. Hope this helps:

Open the installer and leave it in the background.

One fix is to go into the "temp" folder, located in
c: -> users -> (your username) -> AppData -> local -> Temp -> gentee (mine had a 17 after gentee)

WARNING: If you are not seeing AppData, enable an option called "hidden items" in the file explorer. This option is found as a toggle button inside the view menu of the window itself.

Now that you are in this folder, stay in it and don't close the installer.

You will need to open the file called repository (text file), inside you will find a ton of sourceforge links.
Before those sourceforge links, you will see the following:

A build number, Architecture, posix/win32, dwarf/seh/sjlj, revision number

Scroll at the bottom, those are the newest versions, take a x64 build for 64bit cpus, posix, seh and rev 0. **
This should be what you need if you are using a normal windows system. Copy the link and paste it in a browser, the install should start after a bit. **

Now that you have that file installed. Pat yourself in the back, you've gotten far.

You will need to simply put the 7z file into the folder you've opened previously. (The reason you should keep it open, but you can still make your way back to it if you closed it)

And finally, you just click next, choose the right version that you've put into your folder and start installing. Everything should work.

Congrats, and also: why is it so complicated, I'm just trying to learn C and I have to do all of this, it's not getting to a good start.
Happy Programming!