Copilot change history in Excel: the edits it cannot see

What does the change history skill in Copilot actually do?

Microsoft calls this feature a skill. A skill is just one specific job Copilot knows how to do inside Excel, and this one answers questions about past edits. The Copilot in Excel change history help page says it can catch you up on recent changes, identify who changed a cell and when, and summarise changes over a certain time period.

You use it by typing a normal question in the Copilot pane. Microsoft gives examples like “Catch me up on the changes to this workbook”, “Summarize the changes made to this workbook in the past seven days” and “What changes has Copilot made to this workbook?”. That last question is useful, because it lets you check what an AI did to your numbers after the fact.

The feature became generally available at the start of September 2026. Microsoft announced this on the Excel blog in Copilot in Excel: bringing clarity to collaborative workbooks. It is genuinely quicker than scrolling the Changes pane by hand, and I would use it myself for a quick catch-up on any shared file.

But look at the bottom of the same help page. It says some edits might not appear if they were made with an unsupported version of Excel or with a feature that is not tracked. It also sends you to Review, then Show Changes, when you want to check things by hand. That tells you where Copilot gets its answers, and it means the limits of Show Changes are Copilot’s limits too.

Which edits does Excel never record at all?

Some kinds of change never go into the record in the first place. Microsoft’s Show Changes help page says the pane shows changes to cell values and formulas, including moving, sorting, inserting and deleting cells or ranges. But then it lists what is not tracked yet.

That list includes chart, shape and other object edits, PivotTable operations, formatting changes, and hiding cells or ranges or filtering. None of these are strange edge cases. They are the normal edits people make every day in a report.

Here is why that matters with real examples. Someone applies a number format with no decimals to a price column, so 4.6 now shows as 5 on the screen. The actual value did not change, so nothing is recorded, but the printed report now reads differently. Or someone hides a row that holds a refund. A total that uses SUBTOTAL or AGGREGATE can then leave that row out, and the record still says nothing, because hiding and filtering are not tracked at all.

PivotTables are a bigger gap for anyone who reports to a manager. If a colleague drags a field out of a PivotTable or changes its filter, the summary everyone reads has changed, but there is no entry for it. I covered this kind of quiet damage in my checklist for spreadsheet errors that never show up as errors, and the untracked list above shows the same problem in a new place.

What can wipe the change history clean?

The second problem is worse, because it hides the edits that normally would be tracked. Microsoft has a whole section on its help page for the case where the Changes pane is empty but you know changes were made. It gives three causes for this.

The first cause is someone editing from a one-time purchase or older version of Excel. A one-time purchase is the Excel you buy once and own, like Excel 2019 or Excel 2021, as opposed to the Microsoft 365 subscription. Microsoft says edits made that way cannot be tracked, and they can empty the pane. This is very common with clients, because a lot of small companies still run a boxed copy of Office.

The second cause is using an Excel feature that is not fully supported in co-authoring yet. Co-authoring is the mode where several people edit the same file at once, and a few older features do not work inside it. The third cause is the one that surprised me most. Uploading the file, using Save a copy, or replacing the file can all leave the pane empty, and those are the normal ways people pass a workbook around.

Then there is a reset button. The help page says you can clear the history from File, then Info, when the file is open in Excel for the web. Confirming this clears the Changes pane for everyone using the workbook, and it cannot be undone. The page does not say this needs an owner or an admin. So as far as the documentation goes, anyone who can edit the file and open it in the browser can do it.

Microsoft adds one sentence that saves you here. Resetting does not clear all traces, and things like revision logs and version history might still show earlier changes. So the pane is just the easy record, and Version History is the one that is harder to lose.

Why do macro and AI add-in edits lose their old value?

There is one more answer on the help page, and it matters more now than it did a year ago. Under the heading “Some of my changes are missing previous values”, Microsoft says this happens when values were edited through code. They give examples like editing through VBA or using an add-in.

VBA is the macro language built into Excel. An add-in is a separate program that runs inside Excel, and it usually sits as a panel on the right. So when a macro fills a column, the record can show that the cell changed but not what it held before. The old number is exactly the part you actually need when something goes wrong.

The AI tools people now use inside Excel are add-ins. Claude for Excel is an add-in, and so is ChatGPT for Excel. By Microsoft’s own wording, an edit made by either one falls into the “edited through code” case. So you should not count on the record to hold the previous value for cells they changed.

Copilot’s own edits are a different case. Copilot is built into Excel, and Microsoft gives “What changes has Copilot made to this workbook?” as an example question. This means it is clearly meant to answer for its own work. The practical fix for every other tool is the same one the vendors already ask for. You work on a copy first, and keep the original until you have checked each changed cell.

How far back does the change history actually go?

This is where the documentation does not quite line up. The Copilot help page says Excel tracks supported changes for up to 365 days. The Show Changes help page only says the pane shows the most recent changes, and it gives no number. One popular guide to Show Changes says 60 days.

I would not build a process on any of those numbers. The 365 day figure is the newest and it comes from Microsoft’s own Copilot page, so it is the best one we have. But a single re-upload or reset in the middle of that year empties the record anyway. So the real length of your history is just from the last wipe to today.

Version History is the answer for anything older. Microsoft says to use File, then Info, then Version History, and pick a version to preview it. It shows you whole saved copies of the workbook, so it is slower to read than a simple list of edits. But it is the record that actually survives the events I mentioned before.

How do you keep a trail you can trust on a shared workbook?

None of this makes the Copilot feature useless. It is still a fast way to catch up on a busy file. It just should not be the only record you rely on when money or a client relationship depends on the answer. This is the routine I would follow on any workbook I share.

1. 01
   Keep one file in one place

   Share a link to the file in OneDrive or SharePoint instead of emailing copies. Every upload, Save a copy or replaced file is a chance for the history to come up empty.
2. 02
   Ask who edits in an older Excel

   If a client or colleague opens the file in Excel 2019 or another one-time purchase version, their edits are not tracked. Ask them to use Excel for the web for this file.
3. 03
   Work on a copy before any macro or AI add-in runs

   The record may keep the new value and lose the old one. Your untouched copy is the only place the old values are guaranteed to be.
4. 04
   Read a Copilot summary as a starting point

   If it finds nothing, that means nothing tracked. Check the untracked list: formatting, PivotTables, charts, hidden rows and filters.
5. 05
   Use Version History for anything you have to prove

   File, then Info, then Version History. Open the version from before the problem and compare the numbers yourself.

When the question is not who changed a number but whether a number is right, the change record will not help you at all. For that I use the short test in how to check if ChatGPT or Copilot got your Excel numbers right. That test works on any workbook, no matter how it got its numbers.