The novelist, best known for creating literary sleuth Dr. Kay Scarpetta, is facing off against her former money managers at New York-based company Anchin, Block & Anchin amid allegations they mismanaged her multi-million dollar fortune.
The case has gone to trial in Boston, Massachusetts and Cornwell took the stand on Thursday (07Feb13).
During her testimony, Cornwell claimed her accountants had been charged with organising renovations to her home, which dragged on and disrupted her writing, and they failed to find her somewhere more suitable to work, prompting her to miss a book deadline for the first time in her life.
She insists the situation left her feeling ""extremely stressed"" and lost her a year's income - around $15 million (£9.4 million).
Cornwell told the court, ""This was very destabilising. I really lost my ability to focus and concentrate. I did not know what the book was about anymore. I was just lost. I was adrift. I was extremely stressed.""
The writer's former financial managers deny allegations they mismanaged the account and insist Cornwell squandered her fortune on a lavish lifestyle. The case continues.