According to Google, the outage for some Google Drive users should be completely resolved.

Still having a problem? Then Google want to hear about it:

The problem with Google Drive should be resolved. We apologize for the inconvenience and thank you for your patience and continued support. Please rest assured that system reliability is a top priority at Google, and we are making continuous improvements to make our systems better. If you are still experiencing an issue, please contact us via the Google Help Center.