Copilot returning error "something went wrong"

Question

An account-specific Copilot data corruption bug triggered by creating/deleting an AI agent.

• Another Microsoft account works on the same devices.
• Issue started immediately after creating and deleting an AI agent.
• Responses stream completely, then disappear.
• Sidebar conversation history updates at the exact moment of failure.
• Console error: Virtualizer index less than zero, cannot render child rows.
• Stack trace includes unstable_scheduleCallback.

Answer 1

Hello @Reilly, Morgan,

Thank you for sharing the details of your issue. 

I’ve reviewed the situation, and I want to assure you that this problem is not caused by anything on your side. It has been identified as a service incident by Microsoft and is currently being addressed.  

Here is the information:  

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Title: Users are unable to submit a prompt in Microsoft 365 Copilot Chat and receive an error message

Summary of Impact: Users of Microsoft 365 Copilot Chat are unable to submit prompts. When they attempt to do so, the service fails and returns a generic “Something went wrong.” error message, preventing normal use of Copilot Chat functionality. The issue is currently under active investigation and has not yet been resolved.

Impact Time: Start: Monday, June 15, 2026, at 06:12 UTC. End: Ongoing (incident not yet resolved as of the latest update).

Scope of Impact: The incident impacts Microsoft 365 Copilot Chat. Affected users cannot successfully submit prompts and instead receive an error message. Current indications suggest that less than 50 percent of users are affected, although the exact scope is still being validated.

Action Taken: Engineering teams are investigating using customer case data, HAR files, client-side logs, and service telemetry. They are also trying to reproduce the issue internally and reviewing recent service changes that might be related. Updates are being shared regularly as the investigation continues.

Contributing Factors: The root cause has not yet been confirmed. The team is still analyzing logs, telemetry, and recent changes to determine what’s triggering this behavior.

Next Steps: The investigation is ongoing, with continued analysis of logs and telemetry, internal testing, and correlation with recent updates. Further updates are expected as progress is made.

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Regarding this issue, since it appears to be related to a broader service incident, you may also consider reaching out to your IT administrator. They will be able to check the latest updates via the Service Health dashboard and, if needed, report the issue directly to Microsoft for further investigation on the backend.

In addition, you may also consider submitting feedback directly within the application. This helps the product team better understand the impact from the user perspective and prioritize improvements. You can usually do this by selecting the feedback option (as shown in the screenshot) and choosing “Report a problem”.

This can help increase visibility of the issue and ensure it is properly captured by the engineering team.

I’m really sorry for the inconvenience this has caused, please rest assured that Microsoft engineers are working diligently to resolve this issue as quickly as possible. I appreciate your patience and please feel free to update me if there are any changes or if you need further help.

Warm regards,  

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Answer 2

The described behavior isn’t covered in the provided documentation for Copilot or Copilot Studio error handling, and no documented fix exists in the context for an account‑specific “something went wrong” loop tied to creating/deleting an AI agent.

The closest relevant guidance in the context is:

• Generic “Something went wrong”/unexpected error messages are treated as backend or system errors where the recommended action is to retry later or escalate to support if the problem persists.
• In Copilot Studio and Dynamics 365 Sales Copilot scenarios, when Copilot fails in ways not resolved by configuration checks, the guidance is to open a support case and have it escalated.
• For persistent, tenant‑ or account‑specific Copilot issues in Microsoft 365 (including cases where other accounts work fine on the same devices), successful resolutions in practice have required Microsoft support intervention and escalation.

Given that:

1. Another Microsoft account works on the same devices, which strongly suggests an account‑ or backend‑profile issue rather than a local client problem.
2. The issue started immediately after creating and deleting an AI agent, which aligns with the pattern of backend configuration or data issues seen in other Copilot‑related products.
3. The error is reproducible and tied to this specific account, and not covered by the documented Copilot Studio error codes or generic “try again later” cases.

The actionable path supported by the context is:

1. Treat this as a backend/system error rather than a client bug.
2. Collect clear repro details (time, region, account type, exact steps, and the console error Virtualizer index less than zero, cannot render child rows).
3. Open a Microsoft support case for Copilot, explicitly describing it as an account‑specific failure that began after creating/deleting an AI agent and that does not repro with other accounts.
4. Ask for escalation if first‑line troubleshooting (cache, device, network, sign‑out/in, etc.) does not resolve it, because similar Copilot issues in the context were only fixed after escalation and backend changes by Microsoft.

No supported client‑side workaround or repair procedure for this specific corruption scenario is documented in the provided context.

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References:

• Copilot is missing, disabled, or doesn't work correctly
• FAQ about Copilot in Dynamics 365 Sales
• Understand error codes
• Use Copilot to analyze automation activity and ask product questions
• Copilot Rewrite Feature not working in Classic Outlook - Microsoft Q&A
• Whye is Copilot greyed out in Word after all the tricks have been tried? MS 365 Family - Microsoft Q&A
• Microsoft 365 Copilot Retrieval API errors with Authorization Failed - User does not have valid license - Microsoft Q&A
• Unable to log into m365.cloud.microsoft, something went wrong - Microsoft Q&A

Answer 3

Hello everyone,

I would like to share an update regarding the recent issue with Microsoft 365 Copilot Chat.

According to the latest information I received, the issue has now been fully resolved.

Microsoft identified the root cause as a code regression affecting prompt submission and has since mitigated the issue through a configuration update. They have also confirmed with impacted users that the service is now functioning normally.

Thank you for your patience while this issue was being addressed. If you are still experiencing any problems, please feel free to let me know and I’ll be happy to assist further.

Kind regards,

Answer 4

Hi,

To validate this bug, i tested and can confirm that by uninstalling an agent will trigger this bug behavior in your web env. This doesn't persist into the work env for tenant focused grounded chat sessions.

Best of Luck and Warm Regards

Raji Hameed

Answer 5

Hi Reilly, Morgan,

I understand how frustrating this must be, especially since Copilot appears to generate the response first and then the response disappears afterward.

To help narrow this down, could you please confirm a few details?

• Are you using a personal Microsoft account or a work/school account?
• Does the same issue happen on Copilot on the web as well, or only in the Windows Copilot app?
• If you start a completely new chat, does the response still disappear after it finishes generating?
• Was the AI agent created from Copilot, Microsoft 365 Copilot, Copilot Studio, or another agent experience?
• Have you tried deleting the conversation that started around the time the agent was created/deleted, if it is visible in your history?

In the meantime, please try the following checks:

• Test Copilot from the web Open Copilot on the web in Microsoft Edge and sign in with the same affected account.
• Try an InPrivate window Open Edge InPrivate mode, sign in only with the affected account, and test a new Copilot chat.
• Sign out and back in Sign out of Copilot completely, close the Copilot app/browser, then reopen it and sign back in with the affected account only.
• Repair or reset the Copilot app Go to Settings > Apps > Installed apps > Microsoft Copilot > Advanced options, then try Repair first. If the issue continues, try Reset. Please note that Reset may clear local app data, but it should not delete the Microsoft account itself.
• Update related components Please make sure Windows, Microsoft Edge, Microsoft Edge WebView2 Runtime, and Microsoft Store apps are fully updated, then restart the device and test again.
• If possible, remove or avoid the affected agent/conversation temporarily If the agent or the related conversation still appears anywhere in Copilot or Microsoft 365 Copilot, try removing it or starting a fresh conversation without using that agent to see whether the issue changes.

While my initial response may not fully resolve the issue, I truly appreciate your cooperation as we work together toward identifying the most effective solution. Thank you so much for your understanding. 

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