TechnitiumSoftware/DnsServer · warning · InvalidDataException

StatCounter version not supported.

Error message

StatCounter version not supported.

What it means

Thrown by the StatCounter(BinaryReader) constructor when the version byte (after 'SC') is not in the handled set {1..9}. Each case migrates an older StatCounter layout (newer versions add fields like authoritative counts, response codes, EDNS, blocked stats, error IP addresses). The default rejects unrecognized versions to prevent buffer misalignment when reading the many counter fields.

Source

Thrown at DnsServerCore/Dns/StatsManager.cs:2059

                            _queries = new ConcurrentDictionary<DnsQuestionRecord, Counter>(1, count);

                            for (int i = 0; i < count; i++)
                                _queries.TryAdd(new DnsQuestionRecord(bR.BaseStream), new Counter(bR.ReadInt64()));
                        }

                        if (version <= 8)
                        {
                            int count = bR.ReadInt32();
                            ConcurrentDictionary<IPAddress, Counter> errorIpAddresses = new ConcurrentDictionary<IPAddress, Counter>(1, count);

                            for (int i = 0; i < count; i++)
                                errorIpAddresses.TryAdd(IPAddressExtensions.ReadFrom(bR), new Counter(bR.ReadInt64()));
                        }

                        break;

                    default:
                        throw new InvalidDataException("StatCounter version not supported.");
                }

                _locked = true;
            }

            #endregion

            #region private

            private static List<KeyValuePair<string, T>> GetTopList<T>(List<KeyValuePair<string, T>> list, int limit) where T : DashboardStats.TopStats
            {
                list.Sort(delegate (KeyValuePair<string, T> item1, KeyValuePair<string, T> item2)
                {
                    return item2.Value.Hits.CompareTo(item1.Value.Hits);
                });

                if (list.Count > limit)
                    list.RemoveRange(limit, list.Count - limit);

View on GitHub (pinned to d0484b6c1e)

Solutions

  1. Delete the offending .stat file; the period will be missing from historical stats.
  2. Upgrade to the build that wrote the file, let it run so old files are superseded, then downgrade if needed.
  3. Do not share a stats folder across server builds; use a fresh folder per version.
Defensive patterns

Strategy: fallback

Try / catch

try { counter = new StatCounter(bR); }
catch (InvalidDataException ex) when (ex.Message == "StatCounter version not supported.")
{ counter = new StatCounter(); }

Prevention

When it happens

Trigger: Reading a .stat file whose StatCounter version byte is outside the supported range, typically from a server newer than the running build, a truncated stream, or corruption of the version byte.

Common situations: Server downgrade across a StatCounter format bump; corrupt .stat file; stats folder shared between two server versions.

Related errors

AI-assisted analysis of TechnitiumSoftware/DnsServer@d0484b6c1e (2026-08-13). Data as JSON: /api/errors/827a3f8d492d3928. Report an issue: GitHub.