In rare circumstances, Cisco Catalyst 6000 Series switches can experience a red status light on the supervisor module due to an NVRAM checksum error.
These are the results of this condition:
The output of the show version command shows a checksum failure of some type.
The output of the show test 1 command displays NVRAM:F.
This problem does not impact an operational switch unless configuration changes are made while the switch is in this condition. Refer to Cisco bug ID CSCdx87646.
As a workaround, reset the supervisor module.
Note: Some configuration data can be lost when the switch is reset. Before the switch is reset, be sure to make a copy of the current configuration, and store the copy on another device. In order to accomplish this, issue the show configuration command. Then copy and paste the configuration to a text file.
Catalyst Operating System (CatOS) version 6.4(1) contains a fix for this bug. Refer to Cisco bug ID CSCdz32620.
The fix is also integrated in versions 8.1(1), 7.5(0.19), 7.5(0.28), 8.1(0.10)KIS, and 7.7(0.10)KIS.