For us, so far, the example given in this thread has been working great.
/Volumes/GoogleDrive/*.*
However, I'm now moving over to look at this issue for Windows users. How would one solve it there since volumes are only named with a letter? Seems like it's favoring "G:\" but I guess if it would already be occupied, it would choose another letter. So excluding the "G"-drive doesn't do the trick in all cases. Any ideas?