XL97: How to Modify the Number of Undo Levels

By default Microsoft Excel 97 keeps track of 16 undo levels, which provide an undo history for most actions you perform in Microsoft Excel. You can change the number of undo levels by adding an entry in the Microsoft Windows registry. Microsoft recommends that you do not increase the number of undo levels beyond 100 levels.

NOTE: The more you increase the number of undo levels the more random access memory (RAM) Microsoft Excel requires to store the undo history. This affects the performance of Microsoft Excel.

By default Microsoft Excel 97 allocates RAM for 16 undo levels. The registry setting described in this article allows you to change the default to a value 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 Microsoft Excel allocates for the history. This directly affects the performance of your computer when you run Microsoft Excel. NOTE: When you run a Visual Basic for Applications macro, Microsoft Excel allocates no memory for undoing actions. This feature is disabled for optimization and performance when you run a macro.

Windows 95 and Windows NT 4.0

To use the Registry Editor to change the number of undo levels under Microsoft Windows 95 and Microsoft Windows NT 4.0, use the following steps:

WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall Windows 95 or Windows NT. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk.

For information about how to edit the registry, view the Changing Keys And Values online Help topic in Registry Editor (Regedit.exe). Note that you should make a backup copy of the registry files (System.dat and User.dat) before you edit the registry.

1. Close any programs that are running.
2. On the Start menu, click Run. Type regedit and click OK.
3. In the Registry Editor, expand the following key:

         HKey_CURRENT_USER\Software\Microsoft\Office\8.0\Excel\Microsoft Excel

4. On the Edit menu, point to New and click DWORD Value. With "New Value #1" selected, type UndoHistory, and then press ENTER.
5. On the Edit menu, click Modify. In the Edit DWORD Value dialog box, click Decimal under Base. Type a value between 0 and 100 for Value. Click OK and quit the Registry Editor.
6. Start Microsoft Excel 97. Microsoft Excel stores an undo history for the number of actions you specify in step 5.

Windows NT 3.51

To change the number of undo levels under Microsoft Windows NT 3.51 using the Registry Editor, use the following steps:

WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall Windows NT. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk.

For information about how to edit the registry, view the Changing Keys And Values online Help topic in Registry Editor (Regedit.exe). Note that you should make a backup copy of the registry files (System.dat and User.dat) before you edit the registry.

1. Close any programs that are running.
2. Open Program Manager. On the File menu, click Run. Type regedt32 and click OK.
3. In the Registry Editor, switch to the window for HKey_Current_User.
4. Expand the following key:

         HKEY_CURRENT_USER\Software\Microsoft\Office\8.0\Excel\Microsoft Excel

5. On the Edit menu, click Add Value. In the Add Value dialog box, type UndoHistory in the Name box. In the Data Type list click Reg_Dword and click OK.
6. In the DWord Editor dialog box, click Decimal for Radix. Type a value between 0 and 100 for Data. Click OK and quit the Registry Editor.
7. Start Microsoft Excel 97. Microsoft Excel stores an undo history for the number of actions you specify in step 5.

For more information about undoing an action, click the Index tab in Microsoft Excel Help, type the following text and then double-click the selected text to go to the "undoing, actions" topic.