There’s a nasty bug in the latest version(s) of YAK. It’s definitely present in 1.1.0-experimental and probably in 1.0.3d as well. Basically if you have comments enabled on products, and someone adds a comment, it can wipe the prices.

It’s fixed in trunk (in source control), and I’ll be releasing an updated 1.1.1 version shortly which includes the fix. I’ll also be releasing a patched version of 1.0.3d just in case people don’t want to upgrade to the latest and greatest.

In the meantime, if you’re running either of those versions, I recommend you disable comments on those products for the moment.