How to block renaming files by guests in Teams

Hi @JosOnokiewicz-7040, 

Welcome to Microsoft Q&A forum. 

Thank you for reaching out regarding your concern. I understand that you would like to prevent guests from renaming files.  In Microsoft 365, how this is configured depends on where the files are being accessed from, so please review the following locations to determine which scenario applies to your environment. 

Option 1: Files Accessed Through a Microsoft Teams Channel 

Files shared within a Teams channel are stored in the team’s underlying SharePoint site, and permissions are managed there. 

Steps to update guest permissions: 

1. Open Microsoft Teams and navigate to the relevant Team and Channel. 
2. Select the Files tab and click Open in SharePoint. 
3. In SharePoint, click the Settings icon and choose Site permissions.   

4. Select Advanced permissions settings. 

5. Identify the SharePoint group that contains the guest users (commonly the [Team Name] Members group or a custom guest group). 
6. Select the group and choose Edit User Permissions. 

7. Change the permission level from Edit to Read, then save the changes. 

Option 2: Files Shared Directly from OneDrive or SharePoint 

If files or folders are shared directly (outside of a Teams channel), permissions are controlled by the sharing link or item-level access. 

Steps to restrict guest actions: 

1. Open OneDrive or SharePoint and locate the shared file or folder. 
2. Select Manage access. 

3. Select the existing guest. 
4. Ensure the access level is set to Can view. 

5. Apply the changes. 

I hope this information is helpful. Please follow the steps above and let me know if it works for you. If not, we can continue working together to resolve the issue.  

Thank you for your patience and understanding. If you have any questions or need additional assistance, please don’t hesitate to reach out so I can continue to support you. If you found the response useful, please consider marking it as accepted, as this may help other community members who are looking for similar guidance.  

I look forward to continuing the conversation.   

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To block guests from renaming or deleting files in Microsoft Teams, you can manage permissions at the SharePoint site level, as Teams uses SharePoint for file storage. Here are the steps you can follow:

1. Set Permissions for Guests: You can restrict guests' permissions by setting them to "View Only" or "Read" access. This will prevent them from making changes, including renaming or deleting files.
2. Use Sensitivity Labels: Apply sensitivity labels to your Teams and SharePoint sites to control guest access. You can configure these labels to limit what guests can do, including file modifications.
3. Create Private Channels: If you need to share files with guests but want to restrict their ability to rename or delete, consider using private channels where only specific members can access and edit files.
4. Regularly Review Guest Access: Set up guest access reviews to ensure that only the necessary users have access to sensitive files and that their permissions are appropriate.

By implementing these measures, you can effectively manage the actions guests can take regarding files in Microsoft Teams.

References:

• Governing access in Microsoft 365 groups, Teams, and SharePoint
• Create a more secure guest sharing environment