What happens when an uncorrectable multi-bit error occurs in an ECC memory system?

While ECC memory can correct single-bit errors and detect multi-bit errors, an uncorrectable multi-bit error (e.g., two or more bits flipping in a single memory word that the ECC algorithm cannot resolve) will typically trigger a critical system response. In most cases, the memory controller will signal an uncorrectable error, leading to a system crash (such as a kernel panic in Linux or a Blue Screen of Death in Windows) or a system halt. This behavior is by design, as it prevents corrupted data from being used by the system and potentially propagating further, thus prioritizing data integrity over continuous operation in the face of severe memory damage.