C# Signature:

[DllImport("advapi32.dll", SetLastError=true)]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool AdjustTokenPrivileges(IntPtr TokenHandle,
   [MarshalAs(UnmanagedType.Bool)]bool DisableAllPrivileges,
   ref TOKEN_PRIVILEGES NewState,
   UInt32 BufferLength,
   ref TOKEN_PRIVILEGES PreviousState,
   IntPtr ReturnLength);

VB Signature:

Declare Function AdjustTokenPrivileges Lib "advapi32.dll" (
    ByVal TokenHandle As IntPtr, _
    ByVal DisableAllPrivileges As Boolean, _
    ByRef NewState As TOKEN_PRIVILEGES, _
    ByVal BufferLength As Integer, _
    ByRef PreviousState As TOKEN_PRIVILEGES, _
    ByVal ReturnLength As IntPtr) As Boolean

User-Defined Types:

TOKEN_PRIVILEGES

Notes:

None.

Tips & Tricks:

C#

    If SetLastError is set to true, get the error with this.
        int lastError = System.Runtime.InteropServices.Marshal.GetLastWin32Error();
        Console.Error.WriteLine("NativeErr: " + lastError);
    Then use Error lookup tool for troubleshooting it can be downloaded from MS, ''Err.exe'' I think...

C# Sample Code:

  //This snippet is tested on WinXP and Vista, only needed in Vista when using SetTimeZoneInformation
  Public Class AdjPriv()
  {

    [DllImport("advapi32.dll", ExactSpelling = true, SetLastError = true)]
    internal static extern bool AdjustTokenPrivileges(IntPtr htok, bool disall,
    ref TokPriv1Luid newst, int len, IntPtr prev, IntPtr relen);

    [DllImport("kernel32.dll", ExactSpelling = true)]
    internal static extern IntPtr GetCurrentProcess();

    [DllImport("advapi32.dll", ExactSpelling = true, SetLastError = true)]
    internal static extern bool OpenProcessToken(IntPtr h, int acc, ref IntPtr
    phtok);

    [DllImport("advapi32.dll", SetLastError = true)]
    internal static extern bool LookupPrivilegeValue(string host, string name,
    ref long pluid);

    [StructLayout(LayoutKind.Sequential, Pack = 1)]
    internal struct TokPriv1Luid
    {
        public int Count;
        public long Luid;
        public int Attr;
    }

    internal const int SE_PRIVILEGE_ENABLED = 0x00000002;
    internal const int TOKEN_QUERY = 0x00000008;
    internal const int TOKEN_ADJUST_PRIVILEGES = 0x00000020;
    internal const string SE_TIME_ZONE_NAMETEXT = "SeTimeZonePrivilege"; //http://msdn.microsoft.com/en-us/library/bb530716(VS.85).aspx

    private bool SetPriv()
    {
        try
        {
        bool retVal;
        TokPriv1Luid tp;
        IntPtr hproc = GetCurrentProcess();
        IntPtr htok = IntPtr.Zero;
        retVal = OpenProcessToken(hproc, TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY, ref htok);
        tp.Count = 1;
        tp.Luid = 0;
        tp.Attr = SE_PRIVILEGE_ENABLED;
        retVal = LookupPrivilegeValue(null, SE_TIME_ZONE_NAMETEXT, ref tp.Luid);
        retVal = AdjustTokenPrivileges(htok, false, ref tp, 0, IntPtr.Zero, IntPtr.Zero);
        return retVal;
        }
        catch (Exception ex)
        {
        throw;
        return false;
        }

    }
  }

VB.Net Sample Code:

    Const TOKEN_QUERY As Integer = &H8
    Const TOKEN_ADJUST_PRIVILEGES As Integer = &H20
    Const SE_RESTORE_NAME As String = "SeRestorePrivilege"

    Dim hProc, hToken As IntPtr
    Dim luid_Restore, As Long
    Dim tp As New TOKEN_PRIVILEGES

    ' get the current process's token
    hProc = Process.GetCurrentProcess().Handle
    hToken = IntPtr.Zero
    If Not OpenProcessToken(hProc, TOKEN_ADJUST_PRIVILEGES Or TOKEN_QUERY, hToken) Then
        Return False
    End If

    ' get the LUID for the Restore privilege (provided it already exist)
    luid_Restore = 0
    If Not LookupPrivilegeValue(Nothing, SE_RESTORE_NAME, luid_Restore) Then
        Return False
    End If

    tp.PrivilegeCount = 1
    tp.Privilege.Luid = luid_Restore
    tp.Privilege.Attributes = SE_PRIVILEGE_ENABLED

    ' enable the privileges
    If Not AdjustTokenPrivileges(hToken, False, tp, 0, IntPtr.Zero, IntPtr.Zero) Then
        Return False
    End If

    'good

Alternative Managed API:

Do you know one? Please contribute it!