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SharePoint File Name & Path Validator

Paste file or folder names, one per line, and check them against SharePoint Online and OneDrive rules before you migrate or upload. It flags invalid characters, reserved names, trailing periods and length, and suggests a safe name for each one.

The names you paste are never sent anywhere. All the checking happens in your browser.
Try an example (click to load it into the box)

Lines that contain a / are treated as full paths and checked segment by segment, including the 400-character total path limit.

What SharePoint Online and OneDrive check

  • Blocked characters: " * : < > ? / \ | are not allowed in a name.
  • Reserved names: CON, PRN, AUX, NUL, COM0-COM9, LPT0-LPT9, .lock, desktop.ini, and anything containing _vti_.
  • Periods and spaces: a name cannot end with a period, and leading or trailing spaces are trimmed.
  • Length: the whole decoded path, folders plus file name, must be 400 characters or fewer.
  • Note: current SharePoint Online and OneDrive do allow #, % and &. Older on-premises SharePoint is stricter. This tool checks the current cloud rules.

Disclaimer

These tools are provided free and as-is, with no warranty of any kind. Results are best-effort and can be incomplete or out of date, so always verify them against official Microsoft documentation before you act on them.

fivenumber tools is an independent project and is not affiliated with, sponsored by, or endorsed by Microsoft. Microsoft, Microsoft 365, SharePoint, Entra, OneDrive and Copilot are trademarks of the Microsoft group of companies.

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