I still think that someone could come up with a fix for this, perhaps by hacking the app to tell the Mac OS that it will run on El Capitan, (because perhaps it could) or on fixing the app so it won't update itself without permission, its doing of which, to my mind, is outrageous. So in short, the answer to this problem is you just have to eat it and upgrade your OS to at least Sierra, because their new app combo is not compatible with El Capitan. It puts an icon in the menu bar without option and also puts an icon on the desktop without option (when running). It doesn't appear in the Force Quit window either, so when it hangs up, which in my case would hang up the entire OS, you can't get out of the program without launching Activity Monitor and force-quitting several unannounced background Google apps.

It bears stating that Google does not appear to honor Mac protocol in setting up their desktop streaming clients. It took me days to sort out, and only to get this one app to run. I upgraded the OS on that computer to Sierra, which took quite a bit of doing, as it was one of the 2011 Macs with the overheated/blown graphics display processor which had to be hacked into working at all. I was hoping to find a way to stop it from doing so, but eventually had to give up. Several times, I re-installed the previous version, which would work until it caught on to what I was doing and would again upgrade itself into un-usability. But the new version does not work with El Capitan.

They did this by having their Drive Stream app upgrade itself without permission to the new Google Drive. Google decided to merge the enterprise version of its desktop streaming app (Google Drive File Stream) into its personal desktop streaming app (Google Drive). I am answering this myself from my rather limited experience because there have been no responses and there is almost nothing about this issue on the web right now.

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