Are you building an (like Python or Node.js) to rename these files, or Google Drive changing filename on Android download

: Mac and Windows handle Unicode normalization differently (NFD vs. NFC). If your app syncs files between different operating systems, use a utility like convmv to convert filenames to a consistent NFC form before uploading.

: Sometimes the visible name is fixed, but the underlying metadata still holds the garbled version. Use the Files: update method in the Drive API to simultaneously update the name and mimeType to ensure the correct extension and character set are applied.

: If the garbled text appears in the browser title bar but not in Drive, it may be reading the Document Title from the PDF's internal metadata. You can fix this by opening the file in Adobe Acrobat and updating the Title field under Document Properties .