Comment 2 for bug 932561

That error is saying that windows is unable todetermine the amount of free
space available ona kobo drive. This can happen if the kobo drive has not
"settled" down int he time that calibre waits. A simple workaround is to plugin
your Kobo before starting calibre, wait a minute or so, then start calibre.
Alternatively, try reformatting the sd card/main memory of the Kobo, so that it
settles down faster, or try a smaller sd card.

 status invalid