Yes, the window just closes. No message.
I tested mGalaxy on a different PC now, using a fake rom folder with about 10 zipped text files. All of them showed up in the games list and had screenshot, videos and logos scraped... I know now that all the features CAN work and I'm capable of setting everything up, but it doesn't solve my problem of course..
My PC at home is quite fast, while the wifi is OK-ish. I will do a test tonight, unzipping all the roms and rezipping them, thus getting rid of any comment properties or whatever.
If that doesn't work I'll test the fake rom approach to see if my install of windows 10 is giving mGalaxy trouble.
One thing is for sure, though: I tested the same roms with Launchbox, which worked like a charm without any crashes every time. So even with possible workarounds it is still mGalaxy that would benefit from being more compatible or forgiving with whatever is the issue here...