M365 Copilot-created file placed at unreachable URL: sandbox:/mnt/data

today is Oct 1, still this frustrating sandbox mystery appears. This is not always but today is. Now spent two hours trying to find a solution with M365 Copilot. The result is the same loop. My environment is Macbook Air 15, 2025 / EDGE. Sharepoint but today links. Negative work! Considering to pay for Gemini than this! COPILOT answer . 'What can you do right now?

• If you do not see a blue download link or button for the files, then unfortunately, the platform is currently not allowing file downloads.
• If your organisation has another secure channel (email, Teams, or a file transfer service), I can provide the content or instructions for you to receive the files there—if that’s permitted.
• If you have a technical contact or admin, you may want to ask if file downloads from this chat can be enabled again.

Summary: You have done nothing wrong. The issue is with the current chat platform’s file handling, not with your actions or requests. I am here to help with content, structure, and advice, but I am currently unable to deliver files directly due to these technical restrictions.

If you have another method you’d like to try (email, Teams, file transfer), let me know and I’ll do everything possible to get your files to you. If not, I can provide all the content, speaker notes, and agenda as text for you to copy and paste into your own PowerPoint and PDF files.

Thank you for your patience and for letting me know about the issue.

I think it depends on whether you work in a notebook environment or the conversation environment in coPilot M365. The former creates links to downloadable sites, but they don't work, whereas the latter does, apparently.

Exactly the same output/behavior - I did request the agent to generate a downloadable link, but no luck either! keep sending the sandbox:/mnt/data

Any workaround that had worked so far? Thanks

So MS said they fixed this, but obviously not!

Some users may incorrectly receive suggestions by Microsoft Copilot (Microsoft 365) to generate a file download link

Issue ID: CP1116386

Affected services: Microsoft Copilot (Microsoft 365)

Status: Service restored

Issue type: Advisory

Start time: 11 Jul 2025, 01:00 BST

End time: 4 Aug 2025, 11:00 BST

User impact

Users may have incorrectly received suggestions by Copilot to generate a file download link.

More info

This issue occurred for declarative agents, SharePoint agents, or Copilot notebooks when code interpreter was disabled and users were returned a broken link. When Copilot generated a file, the link provided pointed users to "sandbox:/mnt/data/FILE_NAME" which wasn't an accessible environment.

This behavior was encountered when using either a declarative agent or a notebook.

Users hosted outside of the Government Cloud environment that were using a Copilot declarative agent could have enabled code interpreter to alleviate impact while we continued to investigate this incident.

Scope of impact

Some users may have incorrectly received suggestions by Copilot to generate a file that resulted in a broken download link while code interpreter was disabled.

Root cause

A recent update to help improve Copilot capabilities produced a code issue that was resulting in unexpected suggestions by Copilot.

Next steps

• We're reviewing our update testing and validation procedures to identify opportunities to improve impact detection and better prevent similar future occurrences.

Current status

4 Aug 2025, 17:17 BST

We've completed the deployment of our fix to remediate the issue and received confirmation from a subset of users that impact was successfully resolved. Any users seeing persisting impact are advised to refresh their browser session to ensure they're on the latest build to experience remediation.

This is the final update for the event.

History of updates

1 Aug 2025, 16:48 BST

We've completed validation of the fix and initiated deployment in the affected environments. As deployment progresses, some users may begin to see impact alleviation. Based on current estimates, we expect deployment to complete and the issue to be fully resolved by our next scheduled update.

28 Jul 2025, 17:32 BST

The internal validations of the fix to address the affected declarative agents and Copilot notebooks are now progressing as expected, and we're observing success from our testing. We expect to begin deploying the fix to the affected environment by the end of this week, and we'll provide a timeline for deployment to the affected environment as one becomes available.

25 Jul 2025, 17:19 BST

Due to an issue impacting our internal testing environment, our internal validations of the fix were delayed. We're now proceeding with our initial validations to confirm the efficacy of our fix, and anticipate we'll have a timeline for deployment to the affected environment with our next scheduled update.

23 Jul 2025, 18:17 BST

We're completing our internal validations and tests for our fix to ensure it addresses the affected declarative agents and Copilot notebooks without introducing any unexpected problems to the service. We're expecting the validations to be completed and a timeline for our fix deployment to be available by our next scheduled update.

22 Jul 2025, 16:23 BST

Our internal fix testing and validations are ongoing as we work to ensure it fixes the issue for both declarative agents and impacted notebooks.

21 Jul 2025, 16:38 BST

Our additional root cause analysis has isolated an update to the Copilot service that’s producing a code issue which is resulting in the unexpected suggestions by Copilot. We're developing a fix that will address the code problem and remediate the impact. We're expecting that our internal fix testing and validations will have completed and that an estimated timeline for our fix deployment will be available by our next scheduled update.

17 Jul 2025, 23:28 BST

We've determined that code interpreter must be enabled to generate a file download link and that Copilot is attempting to perform this function when it isn't enabled by default. Based on our improved understanding of this event, we’ve updated the Title, User impact, and Scope of impact fields of our communication. To remediate impact, we're identifying ways of to correct Copilots behavior so that it informs users that this function isn't available if code interpreter isn't enabled.

16 Jul 2025, 23:32 BST

We’re investigating the code interpreter configuration to determine our next troubleshooting steps and what actions we can take to resolve this issue. While we investigate, we’ve validated that users of a Copilot declarative agent can enable code interpreter to alleviate impact while we continue to investigate this incident.

16 Jul 2025, 20:56 BST

We're continuing our analysis of the code interpreter configuration to better understand its relation to the impact before we can progress with the development of a mitigation strategy.

16 Jul 2025, 18:45 BST

Our investigation has led us to suspect the impact may be related to a code interpreter configuration, and we're working to confirm this suspicion before determining our next steps towards mitigation.

16 Jul 2025, 17:31 BST

We're reviewing the HTTP Archive (HAR) logs provided by some affected users to help determine our next troubleshooting steps

16 Jul 2025, 17:00 BST

We're investigating a potential issue with Copilot and checking for impact to your organization. We'll provide an update within 30 minutes.

CoPilot offered the prompt "export as .docx" but this generates the sandbox:/mnt/data/.... which doesn´t work.