MC1194615 – Microsoft Excel: Enabling M365 subscribers to use Copilot Chat in locally stored modern workbooks

Product:

Copilot, Copilot Chat, Microsoft 365 Apps, Microsoft 365 Copilot, OneDrive, SharePoint

Platform:

Online, World tenant

Status:

Change type:

New feature, User impact, Admin impact

Links:

Details:

Summary:
Microsoft 365 subscribers will be able to use Copilot Chat in locally stored Excel modern workbooks starting mid-December 2025, with rollout completing by January 2026. This feature is enabled by default and aligns functionality with workbooks stored in SharePoint or OneDrive.

Details:
We're enabling Microsoft 365 subscribers to use Copilot Chat when working in Microsoft Excel modern workbooks (.xlsx, .xlsb, .xlsm, .ods, .xltx, .xltm, and .xlam files) stored locally. This brings parity with workbooks stored in SharePoint or OneDrive, allowing users to query Copilot Chat regardless of storage location.
[When this will happen]
General Availability (Worldwide): Rollout will begin in mid-December 2025 and is expected to complete in January 2026.

Change Category:
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Scope:
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Release Phase:

Created:
2025-12-12

updated:
2025-12-12

Task Type

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Docu to Check

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MS How does it affect me

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MS Preperations

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MS Urgency

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MS workload name

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summary for non-techies**

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Direct effects for Operations**

User Experience Impact
Users may experience confusion or frustration if they are not prepared for the new Copilot Chat feature in locally stored workbooks, as it may change their workflow unexpectedly.
   - roles: End Users, Data Analysts
   - references: https://learn.microsoft.com/copilot/manage, https://learn.microsoft.com/copilot/overview

Technological Impact
The introduction of Copilot Chat in locally stored workbooks may lead to performance issues or bugs if the infrastructure is not adequately prepared to handle the new feature, potentially causing slowdowns or crashes.
   - roles: IT Support, System Administrators
   - references: https://learn.microsoft.com/copilot/manage, https://learn.microsoft.com/copilot/overview

Configutation Options**

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Data Protection**

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explanation for non-techies**

Microsoft is making a change to how you can use Excel, a tool many of us rely on for organizing data and performing calculations. Imagine Excel as a kitchen where you prepare meals. In this kitchen, there's a new assistant, Copilot Chat, who can help you with your recipes (or in Excel's case, your data and formulas). Previously, this assistant was only available if you stored your recipes in certain cabinets (like SharePoint or OneDrive). Now, starting from mid-December 2025, this assistant will be available to help you even if your recipes are stored in a drawer right in your kitchen (locally on your computer).

This means that if you're working on an Excel file saved directly on your computer, you can still ask Copilot Chat for help without needing to move your file to those specific cabinets. It's like having the flexibility to cook with the ingredients you have on hand, without needing to go to a special pantry.

For those using Microsoft 365, this change will happen automatically, and you won't need to do anything special to start using it. It's designed to make your work more seamless, whether your files are stored locally or in the cloud. This update won't affect how you currently work with files stored in SharePoint or OneDrive, so you can continue using those as you always have.

This change is part of Microsoft's effort to make tools like Excel more accessible and helpful, no matter where you choose to store your files. It's like having a helpful sous-chef in your kitchen, ready to assist you with your data needs, whether you're working from a recipe book on the shelf or a note card in your drawer.