Professional liability insurance, more commonly known as Errors and Omissions (E&Oinsurance), is a special type of coverage that protects your company against claims that a professional service you provided caused your client to suffer financial harm due to mistakes on your part (errors) or because you failed to perform some service (omissions).E&O insurance can cover the cost of defending your company in a civil lawsuit and certain damages awarded, even if the legal action turns out to be groundless. Professional liability insurance is required by law in some areas for certain kinds of professional practices, especially medical and legal, where it is more commonly called malpractice insurance. This type of protection is not part of your general liability insurance or homeowners insurance.