This article was previously published under Q211922
For a Microsoft Excel 97 version of this article, see 162944.
By default, Microsoft Excel keeps track of 16 "undo" levels. Undo levels providean undo history for most actions that you perform in Excel. You canchange the number of undo levels by adding an entry in the MicrosoftWindows registry.
Note We recommend that you do not increase the numberof undo levels beyond 100.The more you increase the number of undo levels, the more random access memory (RAM) Excel requires to store the undo history. This affects the performance of Excel.
By default, Excel allocates RAM for 16 undo levels. Theregistry setting that is described in this article lets you change the defaultvalue to a value that you specify.
If the undo history is set to zero, no memory isallocated for undoing actions. The higher the undo history value, the morememory Excel allocates for the history. This directly affects theperformance of your computer when you run Excel.
Note When you run a Visual Basic for Applications macro, Excel allocates no memory for undoing actions. This feature is disabled foroptimization of performance when you run a macro.
To use Registry Editor to change the number of undo levels, follow these steps.
Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base:
322756 How to back up and restore the registry in Windows
Close any programs that are running.
Click Start, click Run, type regedit in the Open box, and then click OK.
In Registry Editor, expand one of the following registry subkeys, as appropriate for the version of Excel that you are running: