Hmm... I don't know of a particular crash issue with importing a .qbo file. More likely it is an issue with your data file. Try running File->Utilities->Rebuild and then try importing again and see if that corrects the issue.

If you have a lot of matched transactions in your download transactions window (like over a hundred) you could also try deleting them from the download transactions window.  They've already matched so the numbers are already in your register and you can safely remove them.