Unity-Technologies/UnityCsReference · error · Exception

Received corrupted message

Error message

Received corrupted message

What it means

Thrown by the ReadString helper inside PlayerConnectionLogReceiver.LogMessageMultiple when deserializing a log message payload from a connected player and the byte-length prefix of a string field is negative. A negative length indicates the payload is malformed or corrupted — either truncated, byte-misaligned, or from an incompatible player/editor protocol version. The method reads log type, message, timestamp, and stacktrace strings sequentially from the payload buffer.

Source

Thrown at Editor/Mono/PlayerConnectionLogReceiver.cs:137

            var name = ConnectionUIHelper.GetPlayerNameFromId(messageEventArgs.playerId);
            var t = ConnectionUIHelper.GetPlayerType(ProfilerDriver.GetConnectionIdentifier(messageEventArgs.playerId));

            var messagePrefix = $"<i>{t} \"{name}\"</i> ";
            var prefixUtf8Bytes = Encoding.UTF8.GetBytes(messagePrefix);

            fixed (byte* payloadPtr = messageEventArgs.data.AsSpan<byte>())
            fixed (byte* prefixUtf8Ptr = prefixUtf8Bytes)
            {
                static UTF8StringView ReadString(byte* payload, ref int offset)
                {
                    var bytesLength = BitConverter.ToInt32(new ReadOnlySpan<byte>(payload + offset, 4));
                    offset += 4;

                    if (bytesLength == 0)
                        return default;
                    if (bytesLength < 0)
                        throw new Exception("Received corrupted message");

                    var utf8StringPtr = payload + offset;
                    offset += bytesLength;
                    return new UTF8StringView(utf8StringPtr, bytesLength);
                }

                static LogMessageFlags FlagsFromType(LogType type)
                {
                    switch (type)
                    {
                        case LogType.Warning: return LogMessageFlags.DebugWarning;
                        case LogType.Error: return LogMessageFlags.DebugError;
                        case LogType.Assert: return LogMessageFlags.DebugAssert;
                        case LogType.Exception: return LogMessageFlags.DebugException;
                    }
                    return LogMessageFlags.DebugLog;
                }

View on GitHub (pinned to 225b0fbdb5)

Solutions

1. Ensure the connected player is built with the same Unity version as the editor to avoid protocol mismatches.
2. Check the player connection network stability — unstable connections can produce truncated payloads.
3. If developing a custom connection, verify your binary payload matches the expected format (4-byte Int32 length prefix per string field, in order: logType, message, timestamp, stacktrace).

When it happens

Trigger: A connected player (via Player Connection / Profiler connection) sends a log message batch whose binary payload is corrupted or uses an incompatible serialization format. The ReadString function reads a 4-byte Int32 length prefix; if that value is negative, the payload is unrecoverable.

Common situations: Connecting a player built with a different Unity version than the editor; network corruption or packet loss on the player connection; player crash mid-transmission producing a truncated payload; debugging a custom player connection protocol that sends malformed data.

Related errors

• Unexpected resultBits Span length. The expected length of re
• ScriptableBakedReflectionSystemWrapper
• Not a valid handle, has it been released already?
• GetInstallationForPath: Does not allow null editorPath
• GetCodeEditorForPath: Does not allow null editorPath

AI-assisted analysis of Unity-Technologies/UnityCsReference@225b0fbdb5 (2026-08-13). Data as JSON: /api/errors/f55ae3e760573d52. Report an issue: GitHub.