Bucket one: the title exists, you just can't find it
Kentucky allows the owner of record to apply for a duplicate title through the county clerk. It is ordinary paperwork with a small fee. The one thing to check first is that the name on the state's record is actually yours — if the home was bought informally years ago and never transferred, the record may still show a previous owner, and that is a different and larger problem.
Bucket two: there's an old lien that was never released
A loan from a lender that no longer exists is the classic version. The debt was paid decades ago but nobody filed the release, so the encumbrance still shows. Resolving it means tracking the successor institution, or the entity that acquired the loan book, and obtaining a release to record with the clerk.
It is tedious and it is solvable. Do not let a buyer use it to justify a last-minute price cut — a buyer who works in this market should have priced the risk up front.
Bucket three: there is no title, on purpose
This is the Kentucky-specific one. Under the state's conversion process, an owner can surrender the certificate of title and record an affidavit converting the home to real estate. Afterward the home is part of the land, and there is no title to sign over because the state stopped tracking it as a vehicle.
Sellers hit this when a buyer's closing agent asks for a title that legally cannot exist. The fix is documentary, not procedural: show the recorded affidavit and the deed, and sell the home as part of the real estate.