All paths for used assets can be configured (removed when needed) within the 3ds Max configuration under Customize - Configure User Paths - External files – these are stored in the 3dsmax.ini within the [BitmapDirs] section.
Let me add, that generally, we recommend resolving all references used by Forest to absolute UNC paths. It's not necessary, but usually, this way you avoid any texture path issues while using distributed rendering. The "default" file handling is controlled by 3ds Max and could be adjusted under Options - Preference Settings - File Handling - Convert file paths to UNC. This way all your scenes should use UNC paths.
I hope that helps.