Microsoft removed Excel's COPILOT formula on Monday. Spreadsheets using it now break.
The change landed on Monday.
Microsoft's own support page for the function says: "Starting September 14, 2026, the COPILOT function is no longer available in Microsoft Excel."
The function "previously let you provide a prompt and references from the grid to generate a response from an AI language model directly in a cell". According to the same page, it was "previously available only in the Frontier program and the Microsoft 365 Insider program".
Existing work remains as cached values, but no longer updates. When a cell containing the function recalculates, it returns a #NAME? error.
Microsoft's stated replacement is the Copilot pane, which "supports many of the same AI-powered tasks".
That difference matters if you wired the function into a model. A formula can be audited and reviewed in a versioned file. A side pane is a conversation.
If you built a spreadsheet on an AI function that was still in preview, who signed off on that dependency?
Sources
Our file on Microsoft
- 20 Sept
Infor shipped three AI agents into a distributor's ERP in two weeks.
- 19 Sept
Microsoft's AI agents rewrote 430,000 lines of Copilot code. The tokens cost $120,000.
- 17 Sept
Microsoft confirmed an Excel security update can silently break paste. No fix date yet.
- 17 Sept
Broadcom raised VMware prices by 10x or more, European cloud providers say.
- 15 Sept
Microsoft knocked out Remote Desktop with two September security updates.
For your next steering committee
- 1Ask which AI tools already touch your ERP or finance data, including the ones nobody approved.
- 2Ask what each tool is allowed to change, and who reviews what it changed.
- 3Ask how the result is measured, and who decides to switch a tool off.
Issue 01 of the ERP LEADERS brief puts a timeline, the three-number review and six questions on one page. Read issue 01
Welcome back. · Issue 01