Microsoft Excel can maintain and display information about how a worksheet was changed.
Change tracking logs details about workbook changes each time you save a workbook. You can use this history to understand what changes were made, and to accept or reject revisions.
This capability is particularly useful when several users edit a workbook. It's also useful when you submit a workbook to reviewers for comments, and then want to merge input into one copy, selecting which changes and comments to keep.
How change tracking works
When you view the change history (change history: In a shared workbook, information that is maintained about changes made in past editing sessions. The information includes the name of the person who made each change, when the change was made, and what data was changed.), either directly on the worksheet or on a separate History worksheet (History worksheet: A separate worksheet that lists changes being tracked in a shared workbook, including the name of the person who made the change, when and where it was made, what data was deleted or replaced, and how conflicts were resolved.), you see who made each change, what type of change was made, when it was made, what cells were affected, and what data was added or deleted.
Change tracking is available only in shared workbooks (shared workbook: A workbook set up to allow multiple users on a network to view and make changes at the same time. Each user who saves the workbook sees the changes made by other users.). In fact, when you turn on change tracking, the workbook automatically becomes a shared workbook, although you don't have to store the workbook where others can access it.
Change tracking differs from undo and backup Unlike the Undo button, you can't use the change history to back out changes. However, the history includes a record of any deleted data, so that you can copy lost data from the History worksheet back to the original cells. Because change tracking isn't designed to help you return to earlier versions of a workbook, you should continue to back up workbooks that have change tracking in effect.
Some types of changes aren't tracked Changes you make to cell contents are tracked, but other changes, including formatting changes, are not. Some Excel features are unavailable in shared workbooks and therefore aren't tracked.
History is kept only for a set interval When you turn on change tracking, the history is kept for 30 days. This limit keeps workbook size manageable. You can increase or decrease the number of days of history to keep. If you want to keep the history indefinitely, you can specify a large number of days, or you can make periodic copies of the history information.
How history gets deleted Excel determines what history is kept by counting back from the current date. Each time you close the workbook, Excel erases any part of the change history that is older than the number of days in effect the last time the workbook was saved.
For example, if you're keeping 30 days of change history, and you open a workbook for the first time in two months, you'll be able to view the history from two months ago. However, when you close this workbook, the history from 31 to 60 days ago is deleted.
If you turn off change tracking or stop sharing the workbook, all change history is permanently deleted.
How to use change tracking