I'm getting an error when I try to run Sonic R after installing the updater, then running the exe inside and outside the mod loader. I tried this with my original PC copy (Published by SEGA PC with the foil cover) and the Sonic 3D/Sonic R two pack from Expert Software. "The procedure entry point C:\Windows\System32\d3d9.Direct3DCreate9 could not be located in the dynamic link library d3d9.dll." The thing is, my copy of Windows isn't installed on the C drive, but it seems like it won't look anywhere else.
... Yeah, um. In order to hijack d3d9.dll for the mod loader, I had to make it redirect the d3d9 functions to the original dll by giving the absolute path. I'm not sure if there's any way to work around that.
If you have a C drive at all, maybe make a symlink? Or you could try hex editing the path in the updated EXE to point to your actual Windows drive. (Change the C: to a W: or whatever it may be.) The symlink would likely be easier and safer though.
The path isn't in the EXE, it's in the mod loader DLL, which is placed in the Sonic R folder as d3d9.dll.
Oh hey, for once my mod loader might be useful! My Cave Story mod loader hijacks dsound.dll, and I get the original file back by using GetSystemDirectory. https://github.com/Clownacy/Cave-Story-Mod-Loader/blob/master/src/mod_loader_bootstrapper/main.c#L65
Just pushed 1.0.8 of this, added Saturn Style Colors by InvisibleUp (with her permission). In case anyone missed it Sonic R just got a mod that drastically improves the lighting of the environments to more closely match the Saturn version, as well as the 1998 port when running in DirectDraw mode. https://imgur.com/gallery/XkvE92q here's some comparison shots from Radical City I whipped together.
Updated to 1.0.9 to add EggRobo Texture Fix by InvisibleUp. Fixes that long-known goof where tails eye texture would be rendered on EggRobo's blaster. Also updated the fallback copy of the Sonic R Mod Loader to the latest version, which fixes the GameBanana 1-Click Support.
Updated to 1.0.10 to fix two minor bugs in the installer. Corrected a permissions issue, preventing the mod manager from working in rare cases. Included the images for the help file, which for some reason were omitted.