Where are you getting the Thunderbird installer? It should be from: https://www.thunderbird.net/thunderbird/all/ Does the MSI installer have the same problem?

The file was the same I used. I then tried to install die MSI installer version and that only opened a small window for a few seconds with a progress bar and then nothing else happened. The small window vanished and that was it. Nothing else. Thunderbird is the only program I can't install. I was able to install the beta version though.

Do any other installers for different programs work? You could try running the MSI installer again with logging enabled to see what's going wrong. msiexec /i "Thunderbird Setup 115.6.1.msi" /l*v "TB.log"

I tried using the command but my PC says it can't run this installation pack. Every other program I ever installed on this PC had no problems whatsoever. But I have always had problems with Thunderbird of every single PC I owned. I don't know why, I just let the installer to its thing and don't choose any special settings.

The MSI is deprecated in favour of the version from the Microsoft store and does not offer user personalization of install location. I would not use either and grit my teeth while trying out the flatpak version for Linux. The version from thunderbird.net is in my opinion the most reliable.

Thunderbird's default installation is a self executing 7-zip of the installer. Antivirus programs that detect the zip part can and have previously done untold damage and caused loads of corruption to the downloaded installer file when they scan it. Some even prevent the application from running.

To me that is what this looks like. Corruption or some third party software interference.

Hello! I finally had time to take a look at it. For some unknown reason the installation simply worked. I have not removed or installed any other software. I don't know what happened, but I can use the normal Thunderbird version now. Thanks for all your help though!