Comment 13 for bug 212726

upgrade behaviour should improve after RC1 is out as we include at least one more patch that should guard xulrunner from corrupting its XUL cache. However, though that bug might cause this bug in most cases, I think that not all cases will be covered.

In anyway, after RC1 is out we should track duplicates of this bug and in case this issue reappears, take appropriate measures.

Unmilestoning as we cannot reproduce and next upload will hopefully fix all cases.