The sd card is just shy (or calibre loves to mess with me)

Hi!

I need help with a perplexing problem.

When I plug my e-reader calibre 'see' the sd card. But only the first time after an update. After I unplug it, and until the next first time after a update the sdcard doesn't exist.

Also, I have no error text other than the one telling me the is no card in the slot A (or the B (I tested)).
I've tried with calibre, windows and nothing to unplug. No change.
Windows see the card and the device as two separate storage like before the weird bug. Ditto with the e-reader, it still see it.
It's like calibre is sulking or something and is the only one ignoring the card.

I'm with calibre portable v.2.53 (on usb key) with the plugging FanFicFare, KoboTouchExtended, KoboUtilities and recently (aka after the bug coming in) EpubSplit and EpubMerge. All up to date.
Calibre installed on another key have the same problem.
My Kobo Glo is up to date too.
I'm under Windows 7.

Any idea?

It's damn annoying, primarily because I don't understand where to begging to unravel that weird glitch. Enigma without clues are frustrating.
At this point any clue will be cheered.