How to modify the number of undo levels in Excel

By default, Excel allocates RAM for 16 undo levels. The registry setting that is described in this article lets you change the default value to a value that you specify.

If the undo history is set to zero, no memory is allocated for undoing actions. The higher the undo history value, the more memory Excel allocates for the history. This directly affects the performance 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 for optimization 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

1. Close any programs that are running.
2. Click Start, click Run, type regedit in the Open box, and then click OK.
3. In Registry Editor, expand one of the following registry subkeys, as appropriate for the version of Excel that you are running:
   
   Microsoft Office Excel 2007
   HKEY_CURRENT_USER\Software\Microsoft\Office\12.0\Excel\Options
   Microsoft Office Excel 2003
   HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Excel\Options
   Microsoft Excel 2002
   HKEY_CURRENT_USER\Software\Microsoft\Office\10.0\Excel\Options
   Microsoft Excel 2000
   HKEY_CURRENT_USER\Software\Microsoft\Office\9.0\Excel\Options
4. On the Edit menu, point to New, and then click DWORD Value. Select New Value #1, type UndoHistory, and then press ENTER.
5. On the Edit menu, click Modify.
6. In the Edit DWORD Value dialog box, click Decimal under Base. Type a value between 0 and 100 in the Value box, click OK, and then exit Registry Editor.
7. Start Excel. Excel stores an undo history for the number of actions that you specified in step 6.