Batch Import Convert is a 3ds Max script for batch importing selected file types from a folder and its subfolders, then saving the results as Max files at a chosen version. It can optionally grab a viewport preview during the process, and it creates a new folder named Max inside the converted folder to hold the output. Selecting All in the import list processes every listed type.
Beyond imports, the script offers several modes: Import/Export, Import/Save as, Open/Export and Open/Save as. It can open Max and Mat files and save them to an older version, with fixed support for saving material libraries down to a lower version. An option runs MS/MSE scripts in order before the output process. A checkbox converts poly objects to mesh when using Max 2021 or newer and saving to previous versions, which helps avoid vertex distortion.
When importing, the script uses the default import settings; to change them, run one normal import first so the script picks up those changes. The developer recommends converting a single file manually before running a full batch.