Error: Error 1904. Module C:\arcgis\arcexe8x\bin\xxx.dll failed to register

Error Message

When installing ArcGIS, Windows returns the following error:

Error 1904. Module C:\arcgis\arcexe8x\bin\xxx.dll failed to register.
HRESULT -2147467262.
Contact your support personnel 

If the error is ignored, the installation continues until Windows returns another similar error. This continues throughout the installation.


The Microsoft System Files were not properly updated or there are environment variables with blank values.

Solution or Workaround

The following solutions are in order from most likely to least likely.

  • Make sure you have the correct version of the Comcat.dll in C:\WINNT\System32:
    • Windows NT - Version 4.71
    • Windows 2000 - Version 5.00
    • Windows XP - Version 5.0
    See the Related Information section below for the solution.
  • Check your Environment Variables and make sure all have correct values.
    For help with setting a system environment variable, see: How To: Edit an environment variable.
  • Uninstall ArcGIS, remove dao360.dll and then reinstall ArcGIS.
See: HowTo: Update Microsoft System Files on Windows NT 4.0
Do not delete or remove dao360.dll when installing ArcGIS Desktop 9.0 or greater

Related Information

Last Published: 6/17/2016

Article ID: 000004002