Forum Discussion
SharePoint /:f:/r/ links fail from Outlook: %2F becomes %252F
We are seeing a reproducible issue with SharePoint Online folder sharing links (/:f:/r/) sent via Outlook. A freshly generated folder link works when opened directly in Edge. When opening the lin...
This behavior is caused by Microsoft Defender Safe Links rewriting SharePoint folder sharing URLs, which can result in double URL encoding (%2F → %252F) when links are clicked from Outlook. From O365 it calls Safe Links performs URL scanning and rewriting in email messages, which explains why the encoded parameter changes after the first click.
https://learn.microsoft.com/en-us/defender-office-365/safe-links-about
