I'm using a PC with Windows 10. One way to copy files to Google Drive is to use Windows Explorer. I can copy or drag files from my local harddrive to Google Drive accessed via Windows Explorer. Copying files to Drive in this way is quick, certainly much much faster than directly uploading them to Drive via Chrome. When I copy a file over via Windows Explorer, the process commandeers that storage space on my local disk, but when the copy is complete, the storage space is not automatically freed up. My understanding is that this local storage copy is supposed to automatically clear, but I haven't witnessed it, nor do I know under what conditions or events it is supposed to clear. So if I copy over 20 gigs to Drive, my C:\ disk will have 20 gigs less space, even once the copy has finished. Of course, I have the original 20 gigs of the files on my disk, and now 20 gigs on Google Drive, but how do I clear these 20 gigs of copy data on my local disk? I've tried defragmenting, but it did nothing.
Solved. See the discussion here. https://productforums.google.com/forum/#!topic/drive/RLHaLKoe0Tw;context-place=forum/drive
In brief: Don't upload files to Drive or File Stream via Explorer or Finder directly (from one window to another eg). Always upload directly to Drive via Chrome or another supported browser. If you do or have uploaded files via Explorer or Finder, and those files are eating space on your local drive, disconnect and reconnect to Drive. In windows, click the Drive icon in the taskbar, click, the elipp