I don't actually think it is that honestly, 7.10 is the most recent stable version of the program and has been out for a while now, with no reported issue like this that i am aware of. There have been a few beta's since the official release, but it seems clear to me by reading through this again, that you was always on the official release not beta. So i'm at a bit of a loss, it "did" work, then randomly didn't with no update to the program issued for a few weeks now i think we can safely rule out a launchbox update . The only thing you have stated to me that may apply to this issue is that Windows has updated a bit recently, so that's my only line of enquiry at the moment i'm afraid. Especially as Bigbox "previously" worked just fine.
Feel free to fire any other questions at me if you think i can answer them and help with this at all.