Yeah, you can't have any other games running for cards to drop. This program is only useful for when you aren't playing games.

Probably, I only have the Steam Guard email verification on my account and the program works almost perfect, except for the not switching to a single game after the 30 game 2 hour card drop eligibility idle.

Well, you aren't signed in, but the program looks weird as well. Try reinstalling it? That looks like a corrupted program to me. Might just be as simple as signing back in.

Probably an incompatibility with the mobile authenticator, but I don't have a smart device to tell you if it is the same on my end. So unless the creator can make it compatible (if it isn't already and this is another problem) then you'll need to disable it.

Have Windows 10 as well, so it might be a bug with the program and our OS.

You'll need to restart the program for it to start idling one game, since Steam will refuse to drop card if you have more than one game running. Reason for the 30 game idle is to get all those games to card drop eligibility (which requires 2 hours), but for us it seems it doesn't properly switch over to a single game after all those games reach that point.

Did you try doing it again? After I validated the Steam Guard, I had to click on the sign-in to Steam again. If that doesn't work, than maybe it is a privacy issue? Seems like the program wouldn't have any problems with privacy with how it signs into your Steam account though.

Pretty sure if Steam sees you running more than one game at once invalidates your ability to get card drops. The program is used for when you aren't playing games.

Ah, well it is idling 30 games you have that are below 2 hours, since cards only drop after 2 hours. I have noticed that it doesn't properly switch over to a game once all the games have reached 2 hours though. Guess that is a bug with the program.

As long as both "Steam is running" and "Idle Master is connected to Steam" are green, then you are good. Sometimes you just have bad luck, but you'll get them eventually.