I used YAC on OS X for quite a while, and I just got a Windows computer with a 4K display. With the display set at 4K, YAC Library fonts and especially the controls just below the top of the window are very small. I could not find a way to change the font or control size in the preferences.

Also, if I move my Comics folder from OSX to Windows, will the metadata I got from Comic Vine come along with the folder? I'm not sure where that metadata is on Mac, and how to transfer it to Windows. OTOH, YAC Library for Windows sees the folder on Mac (and metadata) just fine. I'm just thinking about moving the entire folder to the PC.

This is in the TODO list, some work is needed to make YACReader dpi independent

The metadata is stored in the folder where you have your library, so it is going to be copied/moved if you move that folder. It is in a hidden folder: .yacreaderlibrary