I bought a G-Drive mobile SSD a few days back and transferred about 200 Mb. Once I plugged it in, it stopped being recognized
All G-Tech drives are pre-formatted to work on Mac only out of the box. If you want it to work on Windows or both platforms you will need to go through the process of removing the Mac only format and setting it up properly.
We have a guide on how to do so as one of our top FAQs on our support page: Format for Windows