id,summary,reporter,owner,description,type,status,component,version,resolution,keywords,cc,guest,host 10128,VirtualBox x64 fails to start a VM with top-down memory allocation and DLL loading is enabled,Alex Vakulenko,,"I was testing some x64 application for 64-bit specific issues and for this I enabled the Top-Down memory allocation and DLL loading in Windows to ensure that the pointer and values are located in the upper portion of memory. I noticed that with these settings VirtualBox fails to start a virtual machine with the following error: Failed to open a session for the virtual machine WinXP. The loader resolved an external symbol to an address to big for the image format. (VERR_SYMBOL_VALUE_TOO_BIG). Result Code: E_FAIL (0x80004005) Component: Console Interface: IConsole {1968b7d3-e3bf-4ceb-99e0-cb7c913317bb} It looks like there is a problem in VB that mistreats large pointers (either by truncating the pointer value, or using it as a signed value somewhere). In order to enable these two settings in Windows, go to registry editor and change or add the ""AllocationPreference"" value of ""HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management"" key to DWORD:0x00100000 as well as add bit 0x2000000 to ""GlobalFlag"" value of ""HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager"" (this will normally be set to 0x20000400 in this case). Then after reboot try starting a virtual machine. You can read about these flags here: http://msdn.microsoft.com/en-us/library/windows/desktop/bb613473(v=vs.85).aspx (at the end of the page) http://technet.microsoft.com/en-us/library/cc779664(WS.10).aspx (search for FLG_LDR_TOP_DOWN) ",defect,closed,other,VirtualBox 4.1.8,fixed,,,Windows,Windows