Legal malpractice insurance policies require, in general, that the insured notify the carrier of all incidents and claims, on penalty of forfeiting coverage.  Here is an interesting article from Wiley Rein on this issue:

"The United States District Court for the Middle District of Florida, applying Florida law, has held that a letter that gave notice of a potential lawsuit and requested information but that did not demand money or advise the recipient to put his insurance carrier on notice did not constitute a "Claim" under a medical malpractice professional liability policy. Myers v. Interstate Fire & Cas. Co., 2008 WL 276055 (M.D. Fla. Jan. 30, 2008).

An insurer issued a claims-made malpractice policy to a physician for a policy period ending June 19, 2003. The policy defined a "Claim" as "a demand for money, or the filing of Suit naming the Named Insured and alleging a Bodily Injury or Property Damage as a result of a Medical Incident."

Counsel for a former patient sent the doctor a letter on September 6, 2002, stating that he had been retained to represent the patient in a "claim for damages" arising from the doctor’s negligence and requesting a copy of any statements made by the patient, as well as a written statement identifying the doctor’s liability carrier. The insurance broker purportedly forwarded this letter to the insurer’s managing agent on September 22, 2002, though the agent had no record of having received it. "