Glo Kobo Glo and Calibre

Windows 8, latest versions of Kobo and Calibre software:

I continue to find that after I have used Calibre, the next time I connect the Glo I get a message that errors have been detected and the disk should be scanned. I click to go ahead with the scan, and everything seems OK with no errors found.

I seem to remember reading somewhere that Calibre either changes or doesn't change something on the disk which leads Windows to think there might be an error. Is this the explanation, or is something amiss?

Thanks,
Tom