This week, a woman called my office and asked if her father could submit a copy of a will to the probate court. An elderly friend of his had recently passed away; during her lifetime she had told her father several times that the will was located in a certain desk drawer. But when he went to look for it after she'd died, all he could find was a copy. No one could find the original.
Rules vary state to state, but generally, if all you can find is a copy of a will, you should still submit that to the probate court. The thing is, you'll have to prove to the court that this is the authentic last will of the person who died and that there wasn't some other original will floating around. To do so, you'll probably have to call witnesses who can testify about the circumstances under which the will was made and provide evidence that the will was never revoked.
None of that is easy -- or cheap. The easiest way to avoid leaving your heirs with this kind of hassle is to make sure you -- and a trusted family member or friend -- know where your original documents are and to keep them in a safe, and accessible, spot.
For a complete guide to collecting and organizing important papers and information, see Get It Together: Organize Your Records So Your Family Won't Have To, by Melanie Cullen and Shae Irving (Nolo).