Increase the number of allowable Undo operations in ArcMap

Summary

The default number of allowable Undo operations for a geodatabase is 30. After 30 consectutive Undo operations, the Undo button will become disabled. This limitation cannot be changed for a personal geodatabase because it is a limit imposed by the MicroSoft Access format. The default limit of 30 can be changed for data stored in SDE by adding a registry key and specifying a value larger than 30 for the key.

Procedure

Warning:
WARNING: This article contains instructions to make specific changes to essential parts of your operating system. If these specific changes are not done correctly, it may cause serious problems to your computer operating system and files. First, ESRI recommends that you make a complete backup of your system, including the registry, before implementing any of the specific changes. It is highly recommended that you consult with your IT/MIS department, or other qualified computer systems professional before proceeding. ESRI cannot guarantee that you can solve problems that result from incorrect use of the Registry Editor utility. Use the Registry Editor utility at your own risk. Note: your operating system and any subsequent service packs may affect these instructions. These instructions are subject to change without notice.

1. Click Start > Run and type in 'regedit'. Click OK.
   
2. Navigate to HKEY_CURRENT_USER > Software > ESRI.
3. Create a new key inside ESRI called Geodatabase.
4. Create a new key inside Geodatabase called Settings.
   
5. Create a new DWORD value inside of Geodatabase called UndoRedoSize.
   
6. Set the UndoRedoSize based on the following:
   
   - A value of 1e or 0x0000001e will allow for the default of 30 Undo operations.
   
   - Increasing the value by increments of 1 will increase the number of allowable Undo operations by increments of 16.
   
   - A value of 2e (0x0000002e) will allow for 46 Undo operations. A value of 3e (0x0000003e) will allow for 62 Undo operations.
7. Close the Registry Editor and open ArcMap.
   

   Note:
   The registry key should not be set without consent from development.