I've just updated Polyphone to 1.8 on my Windows 10 Pro General Purpose PC and it is just not working.
No error messages displayed.
It starts to launch and then just dies.
The weird bit is that it is running fine on my i7 DAW PC without issue!
The only difference I am aware of is that I have a version of Qt installed on the General Purpose machine - could there be a conflict there?
At present I am completely mystified by this behaviour!
You could try to remove all environment variables related to Qt if any, or use the command line to launch Polyphone (not sure you will have more information but it may be worth a try).
If this still not working the next step is to debug...
You can also check that you didn't install a 64-bit version on a 32-bit computer.