As you know, once you post an item up for auction that should be it, and the auction should run its course. However, Blizzard for some reason has based the auction time around the time of you internal PC clock which means with some time resetting locally you can cancel auctions now by setting your clock back on your PC. Set your clock back to behind the time of when the action was posted and it can be cancelled.
While we know that Blizzard plan on allowing you to cancel auctions in 1.03, it looks like this little workaround does the trick also right now.
Here it is in action…
Thanks to Jan for alerting us to this problem.