Windows Service: Can I configure the current working directory?

You could use DLL injection to call SetCurrentDirectory after the process has already launched. This would require you to build an injector application, plus the DLL to inject. Some tutorials exist; probably the two best ones I've found are:

• Three ways to inject your code into another process
• Extending task manager with DLL injection

You'll need a decent amount of C++ programming background (and a working build environment) to get through that.

However, this assumes that the service is looking at the current directory. Another possibility is that it's using %path%. You say that it "starts at system32, tries a few more locations, and eventually its own directory", so this seems more likely to me.

Compare the directories you see in procmon with your %path%. If they're the same, consider modifying either the SYSTEM %path% or the %path% of the user running the service, so that the directory you want it to search is first.

I believe Fred is right, though -- you're unlikely to see any significant performance benefit by doing any of this, unless it's happening very frequently. Simple file open operations are not particularly expensive, especially if it's a local path and the file doesn't actually exist.

Do this within the Service main function:

• Make a call to GetModuleFilename. It will retrieve the module (the exe) filename including path, in the form C:\path\to\exe\your_service.exe.
• Use string manipulations (maybe using std::string function find_last_of()), to find the last backslash. Strip/trim the string from there on to obtain the path to your module and therefore the directory of your exe.
• Make a call to the function SetCurrentDirectory and voila!