Whenever I try to add any CustomThemeResource, it never works... I added the String registry key in the right place, with the path definitely right... I'm getting this error a whole bunch of time: [0x20A4] Failed to load custom theme file (0x80070005) This has been the issue since the first build which added the option, it never worked... Everything else in the debug log looks fine... That looks quite good, ORelio. What tool are you using to edit the resources? -Noel Resource Hacker. It allows to view/extract/replace resources in exe, dll, msstyles files. The PNG file you are looking for can be found in the msstyles file at STREAM/983/1033. Once extracted, you can modify it with any image editor and apply the file with CustomThemeResource registry key. -- Or place it back in the msstyles file but you need to patch your system to use modified msstyles so bigmuscle's method is better