Old liens on a property are kind of like bad pennies -- nobody seems to know how to get rid of them, and they have an annoying habit of turning up when you least expect them.
It's entirely possible for an old, long-ago (and long-forgotten) lien to cause a house sale to come to a grinding halt. If that happens, here are some of your options:
1. Try to locate the lien holder to get a signed release
If you're sure the lien was paid off, it's possible that the lien holder never properly released it. You may have to track that person down (and hope that he or she is still living) to get a signature.
2. Try to prove you paid the lien
Dig through those old files you have and look for proof that the lien was actually paid. You may have a canceled check or a release note tucked away without realizing it.
3. Ask the new title company or bank to accept the risk
This may not be as impossible as it sounds. If the lien is a couple of decades old and appears to be a holdover due to poor documentation, they might push through the new loan anyhow.
4. Take the issue up with the title insurance company
If there's an old mortgage prior to yours showing up on the record (which happens more frequently than you realize), your title company is likely responsible -- as long as you had title insurance. It doesn't matter how long ago you bought your home, the liability may fall on the title company to make things right.
If all else fails, it might be time to speak to an attorney who has experience handling real estate transactions and stubborn liens.