Methods and apparatus, including computer program products, for emulating a memory circuit in a logic emulation system. The system includes at least one log memory associated with the emulated memory. Each log memory location is marked invalid at a predetermined time. The system receives one or more memory write requests after the predetermined time, each memory write request specifying new data to be written to a specified memory location. If a log memory location corresponding to the specified memory location is marked invalid, a pre-write content of the specified memory location is copied to the corresponding log memory location and the corresponding log memory location is marked as valid, prior to writing the new data at the specified memory location in the emulated memory. The emulated memory is restored to the predetermined time by copying a content of each log memory location marked valid to the emulated memory.