# rpc error: code = Internal desc = grpc: error while marshaling: string field contains invalid UTF-8

- **ID:** `go/grpc-internal-status-details`
- **Domain:** go
- **Category:** data_error
- **Verification:** ai_generated
- **Fix Rate:** 80%

## Root Cause

A protobuf string field contains bytes that are not valid UTF-8. Protobuf strings must be valid UTF-8; otherwise, marshaling fails.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| 1.x | active | — | — |

## Workarounds

1. **** (90% success)
   ```
   s = strings.ToValidUTF8(s, "")
   ```
2. **** (85% success)
   ```
   Use utf8.ValidString(s) to check before sending.
   ```

## Dead Ends

- **** — This changes the API contract and may break compatibility. (60% fail)
- **** — This corrupts the data and may not be acceptable. (70% fail)