compress file window goes blank and won't finish

[dapork]

I have to transfer some large files over the internet and I'm trying to compress them beforehand. Twice in a row I start the process and leave it in the background. Then the Finder tells me to check (bouncing icon) and I go to find the window where it showed the compression taking place has become blank, and there's no option to close or maximize the little window, just the option to minimize it.

There is a zip file, but is it complete? I have no idea. If I try to eject the drive that has the file on it it says it can't be ejected cause it's still in use. Yesterday I restarted my computer to get rid of that small window.

Edit:
I found that if I try to compress a smaller file afterwards it makes the little window close, desktop files disappear and reappear, and creates a zip for the newer file instantly (obviously incomplete). It gets rid of the little window but doesn't get me anywhere in terms of compressing files.