I recently tried to update oblivion (v1.0.228) to v1.2.0.416 . however when installing the patch a error pops up saying: old file not found however a file of the same name was found. contents do not match. then when i start up oblivion i'm still playing in the original version and all the grass textures are a somewhat purple like map texture. i have downloaded the north american vanilla patch not the shivering isles. I do not have shivering isles installed or knights of nine. Any ideas on how to successfully fix the old file problem? thank you.

Do you already have mods installed? They may be conflicting with the patch. Try a clean install and then immediately install the 1.2 patch.