C9 crashes opening songs on Mac Mini

I’ve got C9, version 9.0.30, it runs perfectly on my Macbook Pro 15" (2017), the problem occurs when I run C9 on my Mac Mini (2014). I use OSX 10.10.5 on both computers, same C9-version, and I use same songs from my Dropbox folders that are on both computers. I’ve tried to use C8.5 but that didn’t help. This is what happens:
I can open C9 if I “delete pref…” at start up and I can open a C9 template. Some times I can open one of my own songs afterwards, but not every time???
If I open one of my own songs after start with deleted pref, C9 crashes after starting to load channels.
Same results with “disable pref…” and “use current pref…”

This problem suddenly started a few days ago, I haven’t made any changes on my computer (as far as I know).

Can any one help?