PRB: Debugger Reports "WARNING: symbols checksum is wrong"

When debugging a Win32 application on the uniprocessor version of Windows NT, WinDbg displays warning messages that say:

The actual path for Ntdll.dbg will vary depending on where Windows NT is installed on your system. This warning may be generated for symbol files of other system files such as Kernel32.dll also.

WinDbg verifies that the checksum of the DLL matches the checksum stored in the corresponding debugging symbol (.dbg) file to warn you when your debugging symbols don't match the modules being debugged. If the symbols truly are mismatched, then WinDbg will show incorrect function names when you obtain stack traces and set breakpoints.

During installation, Windows NT runs with the multiprocessing kernel and system files. At the end of the installation procedure on uniprocessor Intel x86 machines, the setup program modifies the kernel and other system files to remove spin lock code needed only on multiprocessor systems.

Because the debugging symbol files were created with the multiprocessing system files, this modification causes the checksums of system files to differ from the checksums in the debugging symbol files. It does not change the file size of the system DLLs, any system code, or the addresses of system entry points. The symbol files are still correct, but because the checksums differ, WinDbg reports a warning.

Although this message is benign and can be ignored, this issue is resolved in the latest debugging tools. For more information on these tools, see the following Microsoft Web site:

This behavior is by design.