Windows 7: How many shell32.dll's does Windows use?

On a number of occasions now I have edited my system32\shell32.dll resources, saved the new file, gone through a restart and seen absolutely no difference. I have checked that the file in place is the edited version (it is!) but still the old values are being used. So is the system using a phantom shell32 from elsewhere and, if so, how, why and all those other pertinent questions? How do I get Windows to take notice of what I'm doing?

Win 7 Professional, 32 bit.

You're not allowed to edit that file. Windows will replace it using a cache of unmodified system files. There are supported mechanisms for doing the things you want. Please tell us what it was you were trying to accomplish and we'll try to help you in a way that will not destroy your system.

Ok ... now you've panicked everyone ... I most certainly can and may edit the resources of that file, having taken ownership and applied every possible permission to it and using recognised editors and replacement techniques. Many visual styles and themes depend on replacing the file with a customised version so this is hardly news.

As I already stated, it is not the case that the edited file is being replaced or deleted by the system (nor bringing Windows to its knees!) The edits are still in place after many reboots and start-ups. It is simply that the changes are having no obvious effect which suggests that it is being bypassed in some way or, despite appearances, is not actually the main file used by Windows 7 in the first place.

You might want to try to find some windows modder forums to ask this question.

If you plan on delving into the tricksey world of hacking at system dlls, you will need a LOT more help or be prepared to spend a tremendous amount of time figuring this all out yourself. In fact a lot of people into modding may not even give you much help as they frequently seem to regard those things as trade secrets themselves

But anyway, the question is probably far to specific and "out of bounds" for most or anyone in this specific forum. Windows is complex enough just in the realm of expected use which most of us reside in. Outside of that you end up in some pretty specialized areas.

A fair amount of panic is probably warranted when editing a file as important as shell32.dll. With native code, you often explicitly allocate memory for all loaded resources. Well written code will query for the sizeof the resource prior to allocating memory for it. Not all code is well written. Changing resources out it very risky for exactly this reason.

I suspect that you've changed out icon resources which are cached by Windows so it does not have to open every file to read the icons. See How to Rebuild the Icon Cache in Windows Vista and Windows 7 - The Winhelponline Blog

Yes, I'm well aware of the risk but this is only a variation on something where many have boldly gone before. Unfortunately it's not icons else I would have been prepared for possible caching problems. There is one minor change to a bitmap. Does Windows cache those too?

Bitmaps are frequently stored in many different bit depths and the proper one selected at runtime. Did you change each one? Bitmaps are not cached by the shell that I'm aware of.

No, I thought not too. Yes, all instances have been modified at the appropriate sizes. It's all very weird!

Any update to this? I'm curious to see if the TS solved the issue.

Sorry. I'd forgotten all about this. I am now pretty convinced that there is only one shell32 in operation. It's been through a few changes and I've adopted different ways of making changes since so I can't be absolutely sure but I believe I was simply mistaken in the placement of the resources which actually affected my system set-up at the time.