Cryptic error when exporting VMs in Windows 8 Hyper V (originally composed March 2012)

I recently had an interesting issue with Hyper V in Windows 8 Consumer
Preview (running fantastically on my Acer W500 tablet without any
additional drivers, available from £350 online). As the laptop only has a
32GB internal hard drive and I wanted to run a few VMs for
testing\learning, I needed more room. The SSD hard drive is upgradeable
according to the W500 community, but I didn't want to spend £120ish on a
128GB SSD right now, so spent £22 on a 32GB Class 10 SD card instead (from
play.com).
When moving my VM onto to SD card from Hyper V Manager, I got the a cryptic error. Same issue and error with exporting the VM. I was also unable to copy and
paste the folder using Windows Explorer, getting a differently worded error. I checked the card
was ok by filling it up with several copies of the photos and movies I had
on the W500. These copied fine (getting a fairly steady 12MBs write rate
BTW), so I knew I didn't have what looked like a 32G card but was actually a much smaller card.
It was then that I had my brainwave - if Windows Explorer can't copy the
files but the media is OK, maybe the files themselves have extra
properties or attributes which cannot be written to the card. I
immediately thought of NTFS extended attributes, and realised that the SD card
would have been formatted with FAT by default. I re-formatted the card
with NTFS and this fixed the issue :)