OneDrive can contain duplicate files when the same document is uploaded more than once, edited on different devices, or copied into different folders. Sometimes the files may have different names even though their actual content is identical.

I would not recommend checking duplicates only by filename. A file named `Report.docx` and another named `Report (1).docx` may be identical, but they could also contain different content. Comparing file metadata and actual file data gives a more reliable result.

For larger OneDrive accounts, a duplicate file finder can make this process easier. SysInfo OneDrive Duplicate File Finder  can scan OneDrive storage and identify duplicate files based on file information and binary data rather than depending only on filenames.

After the scan, you can review the duplicate groups and decide which copies are no longer needed. It also provides options to move selected duplicates to the OneDrive Bin or remove them permanently.