This is an announcement to track the status of a high-priority non-public bug in the
XamarinInstaller.exe installer (as downloaded from https://xamarin.com/download or the big blue button on https://store.xamarin.com/account/my/subscription/downloads). That installer was recently re-signed with a new digital certificate, and that update was causing the installer to exit without any error dialogs on some systems.
This problem should now be fixed as of the December 17th update of the installer. On the small chance that the CDN might still be providing any lingering old versions of the installer, I will also leave the new corrected installer version attached to this post.
If you downloaded an old version of the installer from before December 17, downloading the new latest version from the website will hopefully stop the problem.
In the new version from https://xamarin.com/download still causes trouble, you can instead try downloading, unzipping, and running the updated
XamarinInstaller.exe that is attached on this post.
For reference, the bug report describes the problem as follows:
Download the installer from https://store.xamarin.com/account/my/subscription/downloads.
Run the installer.
The installer quits after step 3 with no error messages.
EDIT Dec 17: This problem should hopefully now be resolved.