# Error Handling

This section lists errors that can occur when SingleStore processes the logs and the snapshots. It also discusses how SingleStore addresses the errors.

## CRC32 Instruction not Supported

If your system hardware does not support the CRC32 instruction, you will receive the following error.

`Warning: SSE4.2 is not supported. Resorting to software CRC32C. SingleStore recovery and log writing performance will be negatively impacted.`

This error will be commonly seen on older processors and some virtualized environments. In this instance, SingleStore will use a software implementation of CRC32; however, this will slow down reading and writing log files. SingleStore recommends that production deployments of SingleStore run on environments that support this instruction.

## Data Corruption Found During Replay

During replay, if SingleStore encounters corrupted logs or snapshots, it puts the database in the `unrecoverable`[state](https://docs.singlestore.com/db/v9.1/reference/sql-reference/show-commands/show-databases.md). Such a database will usually auto-heal if in [High availability, Redundancy-2 mode](https://docs.singlestore.com/db/v9.1/user-and-cluster-administration/high-availability-and-disaster-recovery/replication-and-durability-concepts.md) and the corrupted logs or snapshots are on the replica partitions. During auto-healing, the primary host takes a snapshot and sends it to the replica. When auto-healing is complete, the secondary database will resume its operation in the `replicating` state.

***

Modified at: October 31, 2023

Source: [/db/v9.1/user-and-cluster-administration/high-availability-and-disaster-recovery/transaction-logs-snapshots/errors/](https://docs.singlestore.com/db/v9.1/user-and-cluster-administration/high-availability-and-disaster-recovery/transaction-logs-snapshots/errors/)

(An index of the documentation is available at /llms.txt)