Have you ever checked how many duplicate documents are stored across your SharePoint sites? In large organizations, the same presentation, spreadsheet, or project document may be uploaded several times by different employees. Over time, these copies can consume storage, clutter search results, and make it difficult to identify the latest version.

This issue can become even more noticeable when a company is preparing to consolidate multiple Microsoft 365 tenants. Transferring every duplicate file to the destination can increase the amount of data that needs to be managed. Therefore, reviewing redundant content before or after migration can be a useful part of the planning process.

While exploring available solutions, I found the SysInfo SharePoint Migration Tool, which includes a built-in three-phase deduplication engine. It can identify duplicate files using content hash or file-name comparison. Administrators can also choose whether to retain the latest or oldest copy, depending on their requirements. The product page also describes options to review duplicate groups before deletion.

During SharePoint online migration, I would recommend checking how duplicate detection works and deciding which copy should remain in the destination environment. This is particularly important for documents that have multiple versions or are used by different departments.

Another useful consideration when evaluating SharePoint migration services is whether they offer selective filtering by file extension, creation date, or content type. These controls can help IT teams avoid transferring unnecessary files.

Does your organization clean up duplicate SharePoint documents before migration, or do you handle deduplication after transferring the data? Which approach has worked better for you?