Note: This has happened with v2.4.1 for the first time, but it has happend again since. However, the result of my investigation has always been the same. Therefore this section applies to current versions just as well.
Several times in the past users have reported that their virus scanner detected a virus in the installer for Windows available on my site. I could verify that some virus scanners did indeed detect something, but most others did not. There are several reasons why I'm 100% certain that this was a false positive:
The build process for the installer runs exclusively on Linux. MKVToolNix itself is built on Linux with a mingw cross compiler, and the installer itself is built with a Linux version of the NSIS compiler. Afterwards the installer is uploaded to my Linux-based webserver by the Linux program Unison.
Even on my Linux machine I run an anti virus software which has never detected a virus.
The installer software I use (NSIS – the Nullsoft Scriptable Installation System) has been the victim of being falsely detected as being virus infected in the past. Those cases have all been false positives.
When this problem occured the first time I sent the installer to Kaspersky for verification. Kaspersky replied quickly and confirmed that it was indeed a false positive.