OneDrive resolves file name conflicts when users create or upload files with the same name into the same folder location. This occurs during manual uploads, saving files from applications, or via automated syncing. To prevent overwriting existing files and preserve all user data, OneDrive automatically appends a number in parentheses to the duplicate filename. For example, if Report.docx already exists in the folder, the new conflicting file becomes Report (2).docx. This numbering system clearly differentiates files based on their upload or creation sequence without user intervention.

This conflict resolution is common when multiple users collaborate on shared folders and independently save documents like ProjectPlan.pptx. It also frequently occurs during automatic photo and video uploads from mobile devices to OneDrive, especially when multiple devices capture media with generic filenames like IMG_1234.jpg or VID_5678.mp4. Desktop syncing (OneDrive.exe) also uses this mechanism when a file dragged to the syncing folder has an identical name to an existing online file.

This auto-renaming ensures data integrity by preventing accidental overwrites and loss. However, it can lead to cluttered folders with many renamed versions, requiring periodic user cleanup. While simple and safe, it shifts the responsibility to the user for identifying the latest or correct version among numbered files. This straightforward approach minimizes technical support needs and contributes to OneDrive's broad adoption for secure personal and business file storage.