My computer was turned off due to a power shut down caused by a tempest. Then, when I reopened the game, I had no achievements again.
Environment
Windows XP SP3 (because Minecraft doesn't appears to work well on Ubuntu)
Java Version 7 Update 9
Linked issues
duplicates 1
Comments 3
I lost in the update OK, as MC-519 show, but this time was due to the lack of power supply.
It looks to me like a decent fix for MC-529 will resolve this, even if the cause was different.
Duplicate of MC-519