This is for sure not blocking you from using MuseScore, not even from hearing some playback.
Sample score needed, and steps to reproduce.
Which soundfont(s) are you using?
I have same issue in 3.0.5 version. I reproduced this by opening guitar pro format file. All instruments sounded as grand piano (even drums) until I changed all the sounds manually.
Comments
This is for sure not blocking you from using MuseScore, not even from hearing some playback.
Sample score needed, and steps to reproduce.
Which soundfont(s) are you using?
Are you by change using MuseScore 3.0.3? If so ti'd be a know problem, so upgrade to 3.0.5 (or even 3.1 Beta 2)
In reply to Are you by change using… by Jojo-Schmitz
I have same issue in 3.0.5 version. I reproduced this by opening guitar pro format file. All instruments sounded as grand piano (even drums) until I changed all the sounds manually.
Which soundfont do you have set as the first one in the synthesizer? You can attach a screen shot of it if you like.
"I have same issue in 3.0.5 version. I reproduced this by opening guitar pro format file"
Probably this one: #285934: [Guitar Pro] Regression: GP 5/4/3 files Plays Piano Only fixed for the next 3.1
Which may or may not be the OP's problem