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Router loses configuration due to faulty or corrupt NVRAM


Core Issue

The router fails to load a previously saved configuration. One of these error messages may be observed:

  • System Bootstrap, Version 11.1(8)CA1, EARLY DEPLOYMENT RELEASE SOFTWARE (fc1)
    Copyright (c) 1997 by cisco Systems, Inc.
    Warning: monitor nvram area is corrupt ... using default values
  • Warning: NVRAM size is 0

  • environment checksum in NVRAM failed

  • Router#show startup-config

    %Error opening nvram:/startup-config (Invalid Checksum)



These error messages usually indicate a hardware failure. To verify, issue the test memory command. This is an example of the command output:

Router#test memory

Test NVRAM card [y/n] ? y


Issue the write erase command and reload the router. If the issue persists, the hardware will need to be replaced.

When hardware replacement is indicated, perform one of these options:

  • If you have a hardware support contract directly with Cisco for this part, use the Service Order Submit Tool to request a replacement part directly.
  • For warranty service, contact the Cisco Technical Assistance Center (TAC) directly at 1-800-553-2447,  or online by using the TAC Service Request Tool.
  • If your product is not covered by contract or warranty, contact your Cisco partner or reseller to request a replacement part for the hardware component that is causing the issue.