I've been running Locus on my Samsung Chromebook for several years now. I recently had to reset the Chromebook, and now I get this error when trying to login to google drive to import tracks. This has always worked in the past.
I've just started using Locus (Pro) on my Chromebook Pixel and it seems to work fine except when trying to gain authorisation for my Google Drive. I get the error "Unsupported file format..." as shown in the screenshot.