# verifying github.com/foo/bar@v1.2.3: checksum mismatch: downloaded hash (h1:abc123) != expected hash (h1:def456)

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

## Root Cause

The downloaded module content does not match the checksum recorded in go.sum, possibly due to a corrupted download or a malicious proxy.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| 1.11 | active | — | — |
| 1.17 | active | — | — |
| 1.22 | active | — | — |

## Workarounds

1. **** (70% success)
   ```
   go mod download github.com/foo/bar@v1.2.3 && go mod tidy
   ```
2. **** (40% success)
   ```
   GONOSUMDB=github.com/foo/bar go mod download
   ```

## Dead Ends

- **** — If the proxy is serving corrupted data, re-downloading will produce the same mismatch. (50% fail)
- **** — Go will still verify checksums unless you use GONOSUMCHECK (deprecated) or GONOSUMDB; this may hide security issues. (60% fail)