# go: verifying module: checksum mismatch

- **ID:** `go/checksum-mismatch-proxy`
- **Domain:** go
- **Category:** module_error
- **Verification:** ai_generated
- **Fix Rate:** 80%

## Root Cause

The go.sum entry for a module version does not match the checksum computed from the downloaded module content, often due to a corrupted download cache or a MITM attack on the proxy.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| 1.17 | active | — | — |

## Workarounds

1. **** (80% success)
   ```
   Remove the problematic module from the module cache: go clean -modcache, then run go mod download to re-download with fresh checksums.
   ```
2. **** (90% success)
   ```
   Use GONOSUMCHECK=* or GONOSUMDB=* to bypass checksum verification for specific modules (temporary, not recommended for production).
   ```

## Dead Ends

- **** — go mod tidy will regenerate go.sum from the proxy, but if the proxy serves corrupted content or is malicious, the same mismatch will recur. (60% fail)
- **** — This flag only affects module resolution, not checksum verification; the mismatch persists. (95% fail)