I have two accounts (work and private) each with a Google Drive mapped to my system (e.g., H: and I:). Google Drive through Windows says my private account's drive is full when I try to drag new files to it.
In some apps, e.g., Chrome, if I try to print something to a PDF stored on it, the print appears to work, because a file appears. However, it's deceptive, because the file has 0 bytes and there's no error.
Other times, if I try to download a file with Chrome specifying a path on the private Google account's drive mapped in Windows, I get "download failed" errors. Basically, I can't create any new files on the Google Drive through the Windows OS.
I've tried rebooting, and it changes nothing. My System (C:) drive is not full. I can create files on my work Google Drive. There are no errors in the Google Drive (system tray) Error List (gear menu). I can add files if I drop them in the Google Drive Web interface (opened in the Chrome Browser). Everything works OK from another (work) PC; the problem is only at home and with the mapped drive through Windows Explorer or from applications trying to write to the mapped drive through the operating system.