I am trying to use NoFullGC registry setting to disable the garbage collector in MSXML. (as per http://support.microsoft.com/kb/304227) This however causes a memory leak each time a background thread in the application calls CoFreeUnusedLibraries(). Is there a solution/work around? Instructions 1) Set "NoFullGC" to 1 reg add HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MSXML60 /v NoFullGC /t REG_DWORD /d 1 2) Compile this program For example: cl /MD /W4 /WX msxml_leak.cpp 3) Run and check memory use in taskmgr: it increases over time 4) Remove the registry key reg delete HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MSXML60 /v NoFullGC Notes Also leaks with MSXML30/DOMDocument30 and MSXML40/DOMDocument40 Environment msxml6.dll (6.20.1099.0) on Windows Server 2003 Analysis When the Tls slot is 0 on entry to DllCanUnloadNow() the msxml library allocates memory in AllocTlsData. However it doesn't appear to free it, and when GC is disabled the memory simply leaks. -------------------------- msxml_leak.cpp ------------------------ #include <windows.h> #include <process.h> #include <stdio.h> #import "msxml6.dll" void Check(void*) { CoInitialize(0); for ( int i = 0; i != 10000000; ++i) { CoFreeUnusedLibraries(); ::Sleep(1); } CoUninitialize(); } int main() { CoInitialize(0); { MSXML2::IXMLDOMDocumentPtr pXmlDoc; pXmlDoc.CreateInstance(__uuidof(MSXML2::DOMDocument60)); _beginthread(Check, 0, 0); MessageBox(NULL, "Press when finished", "Msxml leak tester", MB_OK); } CoUninitialize(); }

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