The priority for fixing a bug should be a function of several things:
- When this bug happens, how bad is the impact? ("Severity")
- How often does this bug happen? ("Frequency")
- How much effort would be required to fix this bug? ("Cost")
- What is the risk of fixing this bug? ("Risk")
Two of them are "user questions" (Severity and Frequency), and the other two are "developer questions" (Cost and Risk). Questions 1 and 2 are about the importance of fixing a bug. The answers to Questions 3 and 4 can only make the priority of a bug go down, never up. If the answers to 1 and 2 make it obvious that a bug doesn’t deserve attention, then questions 3 and 4 don’t need to be asked – they are just there for when the first two questions come out with "need to fix this".
A crash is obviously very severe, no matter what the cause. If you lose data because of the crash, that makes it even worse. But I can think of things worse that than that, such as giving the wrong result to some calculation. If a crash happens on a limited set of data, that reduces the frequency of it – so a crash that happens every time you do X is more imporant than crash that happens every time you do X with data Y.