Problem: Cannot edit tables or feature classes in a personal geodatabase
When editing a personal geodatabase in ArcMap, some of the feature classes and tables cannot be edited.
The table has a unique index on a user-managed column. Tables with unique indexes on user-managed columns cannot be edited.
Solution or Workaround
Use ArcCatalog to drop any unique indexes and re-create them as non-unique.
- In ArcCatalog, right-click the feature class or table and open the Feature Class Properties dialog box.
- Click the Indexes tab and use the Delete button to drop the unique index.
- Use the Add button to create a non-unique index.