Microsoft has withdrawn the COPILOT worksheet function from Excel, ending an experimental way to generate artificial-intelligence responses directly inside spreadsheet cells. The company’s support documentation says the function ceased to be available on September 14, 2026, and now retains its explanatory page only as a reference for people who used it in existing workbooks.
The retired function accepted a written prompt together with references to cells in the worksheet. It then sent that context to an AI language model and returned generated material as the result of the formula. That placed an AI request alongside ordinary Excel expressions, allowing it to participate in a workbook’s grid-based workflow rather than requiring a separate conversation panel.
Microsoft’s removal changes how those formulas behave but does not immediately erase output that has already been calculated. According to the support notice, earlier results remain stored as cached values in affected workbooks. The distinction matters when an old file is opened merely to inspect or export its existing contents: the previously generated result can still appear.
The formula itself is no longer recognized, however. If a cell containing COPILOT is forced to recalculate, Excel returns a #NAME? error. In spreadsheet software, that response indicates that the application cannot identify the function named in the formula. Users maintaining files that depended on COPILOT therefore need to avoid treating the cached response as a durable, refreshable calculation. Changes elsewhere in a workbook, an explicit refresh, or another action that triggers recalculation may expose the retired formula.
Microsoft is steering users toward Copilot in Excel instead of an in-cell function. The company says the assistant can be opened through the Copilot icon in the lower-right corner of Excel, where users can describe what they want in natural language. That interface preserves access to AI-assisted spreadsheet work while separating it from the formula language and its automatic calculation cycle.
The support notice does not give a reason for the withdrawal, announce a replacement worksheet function, or provide a migration tool for existing formulas. It also does not say that cached responses will be regenerated. Consequently, workbook owners must distinguish between static remnants of earlier COPILOT calls and live Excel functions that can continue producing updated results.
For organizations that tested the feature, the immediate task is inventory: identify cells using COPILOT, preserve any output that must remain available, and decide whether the work should move to the Copilot interface or another supported spreadsheet process. The retirement is narrow—Copilot remains available in Excel—but it closes the specific route that made generative output look and behave like a native cell formula.
