I have the same problem, only I have 21,000 documents in the queue. I know- for reasons that are hard to explain, the box has been checked by default for years, and we never utilized reminders before now. 

The file is just too monstrous to print either to a pdf  or a regular “offline” printer. The whole thing crashes every time, and takes over an hour just to check all of the invoices to print. 

Why can’t Qb simply have a remove button? They have a remove button after all of the invoices to email later are selected. Such a seemingly simple solution- yet it seems that my only course is to spend a ton of money with a third party to help me, as no one from QB seems to have a solution to a major Design flaw.....