ArcToolbox tools cause ArcMap and ArcCatalog to crash with an error

Description

When attempting to open any tool from ArcToolbox, ArcMap or ArcCatalog crash with the following error message:

"ArcMap.exe has encountered an error and needs to close. We apologize for the inconvenience."

or

"ArcCatalog.exe has encountered an error and needs to close. We apologize for the inconvenience."

The Microsoft error may be followed by additional memory reference errors:

"The instruction at 0x000xx00 referenced memory at 0x000000. The memory could not be 'read'. Click OK to terminate the program."

Cause

There is a known conflict between Microsoft Internet Explorer 7 and the ArcToolbox interface in ArcGIS 9.0 and 9.1. This problem has been resolved in ArcGIS 9.2.

Solution or Workaround

• ArcGIS Desktop 9.0
  Uninstall Internet Explorer 7. Internet Explorer 6 becomes automatically active.
  
  

  Note:
  ArcGIS Desktop 9.0 was moved to Mature Support in May 2005, which means that no more patches or service packs will be provided for this release. See the ArcGIS Desktop Product Life Cycle PDF for more information.

  
  
• ArcGIS Desktop 9.1
  Download the ArcGIS 9.1 Desktop Patch for Internet Explorer 7 Users, or ArcGIS Desktop 9.1 Service Pack 2. See the links in the Related Information Section below.
  
  

  Note:
  Download and install ArcGIS Desktop 9.1 Service Pack 2 if the ArcGIS Desktop 9.1 Student Evaluation or Evaluation version is installed.