Musescore 3.0.5 installation
S1 - Blocker
During installation of Musescore 3.0.5 the following message appear: "The installation source for this product is not available. Verify that the source exists and that you can access it" - Windows 8.1
It is better to ask for help in the Support forum. In general, installation works fine, so something special must be going on with your particuar system that is preventing it.
Meanwhile, a web search for that error message turned up the following: https://blogs.msdn.microsoft.com/smondal/2009/12/03/the-installation-so…