Solved it! It was a combination of many solutions presented above, but I just had to put them in the right order:
Mac Yosemite Download
- Free Download Mac OS X Yosemite 10.10.x Google Drive Fshare. General Requirements. MacBook Air (late 2008 or later) MacBook (late 2008 aluminum or later) MacBook Pro (mid 2007 or later) iMac (mid 2007 or later) Mac mini (early 2009 or later).
- Download Mac OS X Maverics, Yosemite, El Capitan or Sierra! This is a no nonsense method. All OS X's are 100% from the App store and are on my Google Drive f.
- Chrome theme designed for Mac OS X 10.10 Yosemite. I have a MacBook Air and I downloaded this on my Windows custom rig. I just wanted the cool little iOS.
Apple released the new Mac OS X 10.10 Yosemite in the Mac App Store for everyone to download and install for free on October 16th, 2014, but downloading a 5+ GB file for each of your computers will take some serious time. The best thing to do is download it once and create a bootable install USB drive from the file for all of your Macs.
I deleted the Google Drive File Stream app, emptied the trash
I reinstalled the app (still gave an error when trying to log in)
I went to the Finder folder Library --> Application Support --> Google.
Google Drive For Mac Yosemite 10.10
I renamed the folder DriveFS to DriveFS.old
I was now able to log into the app, but it still gave an error accessing the files:
I then went to GO --> Utilities --> Terminal in order to overwrite the Gatekeeper
I entered: sudo spctl --master-disable
Then I entered my password (it’s not visible that you enter something, but the key strokes are noted)
After this I went to system preferences --> Security & Privacy
Under ‘Allow apps downloaded from’ the option ‘Anywhere’ was now visible and automatically enabled
Also, it now showed the text ‘System software from developer “Google, Inc.” was blocked from loading’. --> click 'Allow'
Then when reopening the app, it would start downloading all my files.