Does a mutual release of all claims preclude a plaintiff from suing for damages?

Instead, in its opposition to the summary judgment motion, Bio-Tek relied on Persson v. Smart Inventions, Inc. (2005) 125 Cal.App.4th 1141 (Persson) to argue that the court had equitable power to set aside the release. In Persson, a shareholder was fraudulently induced to sell his shares to another shareholder for less than their market value in a buyout agreement that included a mutual release. (Id. at pp. 1149-1150.) The court held the release was not an essential object of the contract, and setting it aside would not constitute partial rescission. (Id. at p. 1154.) The plaintiff thus could affirm the contract and sue for fraud despite the release of unknown claims. (Id. at p. 1154.) Similarly, in Sime v. Malouf (1949) 95 Cal.App.2d 82, 112-113 (Sime), on which Bio-Tek also relies, a general release of all claims as part of a fraudulently induced sale of the plaintiff's interest in a joint venture did not preclude a suit for damages. Nor was the plaintiff required to rescind the sale and restore the consideration he received because his right to it was independent of the release. (Id. at p. 111.)