There is a similar report on launchpad.
For those affected, the suggestion in the report is not to use "Safely Extract Drive" (Natty) or "Safely Remove" (Precise) (as shown in the picture below) but to unmount the drive from the command line.
The issue is that where a USB memory stick is unmounted before removal (i.e. use Safely Extract Drive), SD cards use-case are apparently treated differently - the use case is that SDxx memory cards are expected to be ejected, leaving the card reader mounted and ready to read the next card inserted.
The workaround for is to use the terminal:
mount -l to list your mounts - your SD card will be reported like the following extract:
/dev/sdb1 on /media/7804-99AA type vfat (rw,nosuid,nodev,uhelper=udisks,uid=1000,gid=1000,shortname=mixed,dmask=0077,utf8=1,showexec,flush)
unmount using the device name shown
Note - if this affects you, subscribe to the launchpad report. During testing with 12.04 I'm perhaps fortunate to be unaffected, but there is a comment in the thread that a user using 12.04 was also affected.
- What is the difference between Eject and Safely Remove Device