peass-ng/PEASS-ng · error · ArgumentException

Resources.Not_A_Valid_Guid

Error message

Resources.Not_A_Valid_Guid

What it means

EnumerateVolumePathNames throws ArgumentException (Resources.Not_A_Valid_Guid) when volumeGuid is non-empty but lacks the required "\\?\Volume{" prefix. Only a volume GUID path is accepted; drive letters and DOS paths are rejected.

Source

Thrown at winPEAS/winPEASexe/winPEAS/3rdParty/AlphaFS/Device/Volume/Volume.EnumerateVolumePathNames.cs:45

using winPEAS._3rdParty.AlphaFS;

namespace Alphaleonis.Win32.Filesystem
{
   public static partial class Volume
   {
      /// <summary>[AlphaFS] Returns an enumerable collection of <see cref="string"/> drive letters and mounted folder paths for the specified volume.</summary>
      /// <returns>An enumerable collection of <see cref="string"/> containing the path names for the specified volume.</returns>
      /// <exception cref="ArgumentNullException"/>
      /// <exception cref="ArgumentException"/>
      /// <param name="volumeGuid">A volume <see cref="Guid"/> path: \\?\Volume{xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}\.</param>
      [SecurityCritical]
      public static IEnumerable<string> EnumerateVolumePathNames(string volumeGuid)
      {
         if (Utils.IsNullOrWhiteSpace(volumeGuid))
            throw new ArgumentNullException("volumeGuid");

         if (!volumeGuid.StartsWith(Path.VolumePrefix + "{", StringComparison.OrdinalIgnoreCase))
            throw new ArgumentException(Resources.Not_A_Valid_Guid, "volumeGuid");


         var volName = Path.AddTrailingDirectorySeparator(volumeGuid, false);


         uint requiredLength = 10;
         var cBuffer = new char[requiredLength];


         using (new NativeMethods.ChangeErrorMode(NativeMethods.ErrorMode.FailCriticalErrors))
            while (!NativeMethods.GetVolumePathNamesForVolumeName(volName, cBuffer, (uint)cBuffer.Length, out requiredLength))
            {
               var lastError = Marshal.GetLastWin32Error();

               switch ((uint)lastError)
               {
                  case Win32Errors.ERROR_MORE_DATA:
                  case Win32Errors.ERROR_INSUFFICIENT_BUFFER:

View on GitHub (pinned to 53fb989abc)

Solutions

1. Normalize input with Volume.GetVolumeGuid(path) before calling
2. Validate the input starts with "\\?\Volume{" and ends with "}\" before calling
3. Catch ArgumentException and log/skip the malformed volume entry

Example fix

// before
Volume.EnumerateVolumePathNames(driveLetter);
// after
var guid = Volume.GetVolumeGuid(driveLetter);
Volume.EnumerateVolumePathNames(guid);

if (!volumeGuid.StartsWith(@"\\?\Volume{", StringComparison.OrdinalIgnoreCase))
    volumeGuid = Volume.GetVolumeGuid(volumeGuid);

static bool IsVolumeGuidPath(string s) => !string.IsNullOrWhiteSpace(s) && s.StartsWith(@"\\?\Volume{", StringComparison.OrdinalIgnoreCase);

try { Volume.EnumerateVolumePathNames(volumeGuid); }
catch (ArgumentException) { Log.Error($"Malformed volume GUID: {volumeGuid}"); }

When it happens

Trigger: Passing "D:\" or "\\?\C:\" to Volume.EnumerateVolumePathNames; passing a GUID with wrong casing of the prefix or missing opening brace; GetVolumeDisplayName forwarding a malformed volume name.

Common situations: Persisted volume identifiers from another tool in a different format; string manipulation that stripped the \\?\Volume{ prefix; assuming drive letters are valid input.

Related errors

• Resources.Not_A_Valid_Guid
• volumeGuid
• volumeGuid
• volumeGuid
• volumePathName

AI-assisted analysis of peass-ng/PEASS-ng@53fb989abc (2026-09-02). Data as JSON: /api/errors/8a674c59cdc32e1a. Report an issue: GitHub.