SATA (Serial ATA) is a mass-storage interface commonly used in modern PCs to connect hard drives to the motherboard. If a PC displays a "SATA device not found" error, it indicates that the operating system cannot detect a connected SATA hard drive. This issue can arise if there is no SATA hard drive installed or if there is a malfunction with the drive or its connection. In some cases, this error may not indicate a critical failure, especially if the system continues to operate normally despite the message. Troubleshooting steps may include checking physical connections, ensuring the drive is properly installed, or addressing any conflicts with other hardware, such as modems.