miauu's Batch Save Obj/Fbx/3ds/Max as .Max files handles batch conversion inside 3ds Max, taking arbitrary .obj, .fbx, .3ds and .max files and saving them out as .max files for a desired Autodesk 3ds Max version. Only files whose checkboxes are turned on get processed and saved.
Files can be gathered two ways. The Get Directory button selects all OBJ/FBX/3DS/MAX files in a chosen folder, and if that folder contains sub-folders the script asks whether to load the OBJ/FBX/3DS files inside them. The Get File(s) button lets you pick individual files, with multiple selections supported so you can open a folder and select several files at once.
The file list responds to mouse input: right-clicking a file name opens its folder in Windows Explorer, while middle-clicking removes that file from the list. A Show Full Path checkbox toggles between the full path and just the file name, which is shown by default. The UI can be resized, and you choose the 3ds Max version the .max files are saved to.