Google-sheets – Convert all Google Docs/Sheets/Slides to Microsoft Office

I figured out the problem. Thanks @Dorje for your help, gave me a hint. :)

The problem was with the file's file extension, it ended with .xlxs, that was the name Microsoft Office 2011 gave it, so I thought it was correct.

I renamed the file with a .xlsx extension, and when I uploaded it again it was correctly encoded in the new language.

For anybody with this problem in the future, the problem is the file extension. :)

The answer is yes. Google Sheets, Docs, Slides and Photos (partially - if downsized) are not counted against Drive space. While inserting images into Docs, Sheets... may sound like a loophole, from a long run it's not very flexible. Inserted images in Sheets tend to broke and dropping too many files into the document will significantly increase the load time eg. slow down the document up to the point when Google document may crash. Another disadvantage would be the limited upload of 1 image at a time.

Also, note that initial files stay on your Drive after conversion, so you will need to delete them.