SD card works only once in Kubuntu 9.04

SD card works only once in Kubuntu 9.04

I have a new MSI GX620 derived laptop, with an internal SD card reader. It works fine when I first insert a card. But when I "safely remove" the card with Dolphin, and stick in a new card, nothing happens. The SD card is not mounted and does not appear in fdisk -l (though I don't know if it's supposed to). It works again when I reboot.