Edge below 146.0.3856.117: Microsoft 365 Copilot chat in the sidebar does not work
Summary
Microsoft confirms that Microsoft Edge versions below 146.0.3856.117 do not work with Microsoft 365 Copilot chat in the sidebar. The internal Edge container page that hosts the chat was changed with Edge Stable 146.0.3856.117 on April 10, 2026. Updating Edge to 146.0.3856.117 or later is the required step.
Symptoms
Microsoft 365 Copilot chat in the sidebar does not work on Edge versions older than 146.0.3856.117. Blocking internal edge:// or chrome-untrusted:// URLs is not recommended, as it can cause unexpected errors and disables the Microsoft 365 Sidebar Copilot Chat experience.
Affected
- Microsoft Edge versions below 146.0.3856.117
- Microsoft 365 Copilot chat in the Edge sidebar
Workaround
No workaround known.
Fix
Update Microsoft Edge to version 146.0.3856.117 or later. This is the minimum supported version for Microsoft 365 Copilot chat in the sidebar.
Recommendation
Check the Edge versions on your devices and make sure Edge updates are not blocked or delayed. Do not block edge:// or chrome-untrusted:// URLs in filters or policies. See the Microsoft allowlist for Edge endpoints.
Sources
- Microsoft Edge: known issues (enterprise) Vendor · learn.microsoft.com
- Allowlist for Microsoft Edge endpoints: Microsoft 365 Copilot Chat Vendor · learn.microsoft.com
Compiled from the sources listed and translated with AI (Claude); status and dates come from the vendor. The vendor’s statements are authoritative. Updated 1 Nov 2026, 18:24.
Where the information comes from
We continuously read the vendors’ official sources, community reports and trade media and summarise them in our own words, with a link to the source:
- Microsoft: Windows release health (Windows 10/11, Server 2016 to 2025), Windows message center, known issues of Microsoft 365 Apps (Outlook, Excel, Word, PowerPoint), Edge, Intune, Autopilot, Windows 365 and Entra Connect, Microsoft KB articles with timelines, Exchange and Windows IT Pro blogs, optionally Microsoft 365 service health and message center
- other vendors: Veeam KB, Citrix (known issues), Ubuntu and Debian (regressions), Broadcom (VMware), Fortinet, Cisco, Mozilla, Let’s Encrypt
- community (title, short excerpt and link only, without the names of the authors): Microsoft Q&A, Microsoft Tech Community (discussions), Veeam R&D Forums, Eleven Forum
- targeted web research with AI (Claude), e.g. on the updates of the month – this also finds discussions on Reddit and in forums; such entries are labelled as community reports until the vendor confirms them
- early warning from trade media (title and link only): Born’s Tech and Windows World, BleepingComputer, AskWoody, Windows Latest, Windows Central, gHacks, The Windows Club, Deskmodder, Dr. Windows, WindowsArea, Frankys Web, heise online
Summary and translation with AI (Claude by Anthropic) – without any data of visitors.
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