For more, see Layer Tools, Fix Layer Integrity
To activate: Layer Tools / General tab
The .shp, .dbf, and .shx components of a Shapefile can become out of sync with one another. The check layer integrity tool analyzes a Shapefile to determine whether there are coinciding records in the three files. Use the Fix Layer Integrity tool if necessary after running the Check Layer Integrity tool.
To Use:
Activate Check Layer Integrity tool.
View the tool Log for results.