_tprintf(_T("Checking process' ACL for problematic entries...\n"));
// prepare to change ACL, open with limited access
process_handle = OpenProcess(WRITE_DAC|READ_CONTROL, FALSE, pid);
if (process_handle == NULL)
{
    _tprintf(_T("Failed to open process 0x%x to adjust ACL: 0x%x\n"), pid, GetLastError());
    return -1;
}

PACL dacl;
ACL_SIZE_INFORMATION acl_info;
PSECURITY_DESCRIPTOR sd;
PVOID ace;
PACCESS_DENIED_ACE ad_ace;
DWORD num_aces = 0;

if (ERROR_SUCCESS != GetSecurityInfo(process_handle, SE_KERNEL_OBJECT, DACL_SECURITY_INFORMATION, 0, 0, &dacl, 0, &sd))
{
    _tprintf(_T("GetSecurityInfo failed: 0x%x\n"), GetLastError());
}

if (!GetAclInformation(dacl, &acl_info, sizeof(acl_info), AclSizeInformation))
{
    _tprintf(_T("GetAclInformation failed: 0x%x\n"), GetLastError());
}

num_aces = acl_info.AceCount;
_tprintf(_T("Number of ACEs: %d\n"), num_aces);
for (int a=0; a<num_aces; a++)  // walk through ACE list
{
    if (!GetAce(dacl, a, &ace))
    {
        _tprintf(_T("GetAce(%d) failed: 0x%x\n"), a, GetLastError());
    }
    if (((PACE_HEADER)ace)->AceType == ACCESS_DENIED_ACE_TYPE)
    {
        _tprintf(_T("Got ACCESS_DENIED ACE (%d)\n"), a);
        ad_ace = (PACCESS_DENIED_ACE)ace;
        DWORD mask = PROCESS_VM_OPERATION|PROCESS_VM_READ|PROCESS_VM_WRITE|PROCESS_SUSPEND_RESUME;
        //_tprintf(_T("ACE mask: 0x%x, target: 0x%x\n"), ad_ace->Mask, mask);
        if ((ad_ace->Mask & mask) != 0) // this ACE denies what we need, remove it
        {
            _tprintf(_T("Deleting ACE %d that denies VM operations\n"), a);
            if (!DeleteAce(dacl, a))
            {
                _tprintf(_T("DeleteAce failed: 0x%x\n"), GetLastError());
            }
            else
            {
                num_aces--;
                if (!SetSecurityInfo(process_handle, SE_KERNEL_OBJECT, DACL_SECURITY_INFORMATION, 0, 0, dacl, 0))
                {
                    _tprintf(_T("SetSecurityInfo failed: 0x%x\n"), GetLastError());
                }
            }
        }
    }
}

LocalFree(sd);
CloseHandle(process_handle);

Checking process' ACL for problematic entries...
Number of ACEs: 4
Got ACCESS_DENIED ACE (0)
Deleting ACE 0 that denies VM operations
SetSecurityInfo failed: 0x7a
Opened \Device\HarddiskVolume2\Program Files\Internet Explorer\iexplore.exe as PID 00000164
Process suspended, 23 threads