I just downloaded music maker 29 thanks to the humble bundle currenly available. However, after the installation is completed, music make don't start. And unfortunately, I have no error message to show.
. . . . However, after the installation is completed . . . .
The first installation (Download Manager) or the 2nd - actual program installation.
There have been issues reported with Antivirus programs Protected Folders/Folder Protection/Ransomware protection creating issues with the installation and program start up.
I had this with Avast - try turning off Protected Folders/Folder Protection/Ransomware feature and re-install the program again.
Do note that Music Maker (MMM) 2021 (v29.x.x.x) has some bugs - see this list - you may be affected by one or more of them Magix are working on them and another patch is due out soon.
Once you have got the program started, after registration/activation there is a third download phase - the Extra Content - these item should appear under the Downloads tab once you are logged into the Store.