Lawyers professional liability (LPL) insurance, also known as errors and omissions (E&O) coverage, provides law firms with protection from costly malpractice or negligence claims. Clients may file lawsuits against their attorneys for certain mistakes, such as misfiling documents and other types of oversights that can result in major payouts from the law firm. Professional liability insurance generally covers certain legal costs, including financial loss incurred by third parties that arise from acts, errors and omissions when providing professional legal services.