QL-Win/QuickLook · warning · InvalidDataException

DS_Store: wrong magic (expected 0x00000001)

Error message

DS_Store: wrong magic (expected 0x00000001)

What it means

Thrown by DSStoreAllocator.ReadHeader when the first big-endian uint32 of the .DS_Store data is not 0x00000001. A genuine .DS_Store begins with the version value 1 followed by the 'Bud1' magic; any other first dword means the file is not a .DS_Store or is corrupt.

Source

Thrown at QuickLook.Plugin/QuickLook.Plugin.ArchiveViewer/DSStore/DSStoreExtractor.cs:71

        public DSStoreAllocator(byte[] data)
        {
            _data = data ?? throw new ArgumentNullException(nameof(data));
            _pos = 0;
            var (offset, size) = ReadHeader();
            _root = NewBlock(offset, size);
            ReadOffsets();
            ReadToc();
            ReadFreeList();
        }

        private (uint offset, uint size) ReadHeader()
        {
            if (_data.Length < 32)
                throw new InvalidDataException("DS_Store header too short");

            uint magic1 = ReadUint32BE(_data, (int)_pos);
            if (magic1 != 1)
                throw new InvalidDataException("DS_Store: wrong magic (expected 0x00000001)");
            _pos += 4;

            uint magic = ReadUint32BE(_data, (int)_pos);
            if (magic != 0x42756431u)
                throw new InvalidDataException("DS_Store: wrong magic (expected 'Bud1')");
            _pos += 4;

            uint offset = ReadUint32BE(_data, (int)_pos); _pos += 4;
            uint size   = ReadUint32BE(_data, (int)_pos); _pos += 4;
            uint offset2 = ReadUint32BE(_data, (int)_pos);
            if (offset != offset2)
                throw new InvalidDataException("DS_Store: root-block offset mismatch");
            _pos += 4;

            return (offset, size);
        }

        private DSStoreBlock NewBlock(uint pos, uint size)

View on GitHub (pinned to cb5d9c429c)

Solutions

1. Validate the first 8 bytes (version 1 + 'Bud1') before parsing.
2. If the file fails validation, skip it or report it as not a valid .DS_Store.
3. Re-obtain the .DS_Store from the original macOS volume.
4. Catch InvalidDataException and return an empty filename list.

Example fix

// before
var names = DSStoreExtractor.GetFileNames(path);

// after
var data = File.ReadAllBytes(path);
if (data.Length < 8 || data[0]!=0||data[1]!=0||data[2]!=0||data[3]!=0x01)
    return new List<string>();
var names = DSStoreExtractor.GetFileNames(path);

// Validate the .DS_Store version dword (must be 0x00000001 big-endian).
public static bool IsValidDsStoreHeader(string path)
{
    var data = File.ReadAllBytes(path);
    return data.Length >= 8
        && data[0] == 0 && data[1] == 0 && data[2] == 0 && data[3] == 0x01;
}

try { var names = DSStoreExtractor.GetFileNames(path); }
catch (InvalidDataException ex) when (ex.Message.Contains("expected 0x00000001"))
{
    // First dword is wrong; file is not a valid .DS_Store.
}

When it happens

Trigger: Calling GetFileNames on a file whose first 4 bytes are not 00 00 00 01: a different binary format, a corrupt .DS_Store, or a file that merely shares the name.

Common situations: A file renamed to .DS_Store that is actually something else; a corrupt download from a network share; an alternative .DS_Store writer that uses a different version dword; endianness confusion from a transfer.

Related errors

• DS_Store: wrong magic (expected 'Bud1')
• DS_Store header too short
• DS_Store: root-block offset mismatch
• DS_Store: not enough data for block
• DS_Store: block id out of range

AI-assisted analysis of QL-Win/QuickLook@cb5d9c429c (2026-08-13). Data as JSON: /api/errors/77f1a22053432fb3. Report an issue: GitHub.