Increasing Undo Levels

As you are working with a worksheet, Excel allows you to “undo” previous actions and return your worksheet to the condition before that action was taken. Normally you use Ctrl+Z to undo an action or you can use the Undo tool on the toolbar.

By default, Excel maintains your last 100 actions, but this number of undo levels can be misleading. There are some actions that can clear out the undo stack, making it impossible to undo any previous actions. For instance, running some macro commands can cause the stack to be cleared. In addition, some actions cannot be undone (they don’t get placed on the stack).

If you find that the Undo command is simply of no use to you, it is possible that the number of undo levels in your installation of Excel has been changed. This cannot be done within Excel itself, but can be done in the Windows Registry. If the Registry value was changed to some very low value, then the undo tool loses meaning. The following Knowledge Base article explains how you can make changes to the proper Registry setting:

http://support.microsoft.com/?kbid=211922

Note that the article in the Knowledge Base says it is for Excel 2000 through 2007. To the best of my knowledge, the Registry-hack approach will still work with later versions of Excel, as well. The only difference is that you’ll need to choose the appropriate Registry key for your version of Excel.

While you can use this technique to increase the number of undo levels as high as you want, Microsoft suggests you don’t increase the undo levels above 100, as there may be a serious hit on the performance of Excel.