A homebuilder (Lopez) assigned all of its lien rights to a lender (MG) to secure construction financing. When the project ran into problems, Lopez tried to file a mechanic's lien but couldn't because it had already given away those rights. The court ruled that once you assign your lien rights to a lender, you lose the ability to file a lien later—even if the lender doesn't pay you. However, you may still sue for breach of contract on other grounds.
Never assign all your lien rights to a lender or anyone else without understanding you're giving up your ability to file a mechanic's lien if things go wrong.
If you must assign lien rights as a condition of financing, carve out exceptions or negotiate the right to file a lien if the lender fails to fund promised draws.
Losing lien rights doesn't eliminate all remedies—you can still sue for breach of contract, but a lien is faster and more powerful, so losing it is a major disadvantage.