App does not start: caught unhandled unknown exception; terminating

After updating to 3.1.7 Toucan does no longer start. It throws out this message instead:

*** Caught unhandled unknown exception; terminating

this seems similar to this issue:
https://portableapps.com/node/58087
I use it on Win 10 Pro 64bit, other Portableapps work. It also works on a second machine with the same OS. Is there a shared library missing probably?
Any tips on where to start debugging?
One thing that might also be a cause: i recently updated .NET-Frameworks with all current hotfixes, the Java-Runtimes and Visual C++ Runtimes on the fault producing machine. Is there something among these that may break Toucan?