Core issue
Different versions of Catalyst OS (CatOS) contain variables that are stored in NVRAM. When the switch initially boots to a newer or older version of CatOS, it will convert the previous configuration to a version usable by the current boot image. During this process a particular memory block that is not needed or usable in the current form will be de-allocated rather than converted. This internal function generates the error message.
Resolution
The following is an example of the console output you will see when this message occurs:
convert_post_SAC_CiscoMIB:Nvram block 0 unconvertible: )
convert_post_SAC_CiscoMIB:Nvram block 1 unconvertible: )
convert_post_SAC_CiscoMIB:Nvram block 2 unconvertible: )
These console messages can also occur when loading a switch configuration generated by another switch, or using a switch configuration from another version of code. A failover to the standby Supervisor Engine can also generate these messages.
The generation of this message is generally informational only. It is a good practice to compare the previous configuration with the current configuration to verify all configuration information was properly converted.
Problem Type
Software issues
Syslog error message received
Catalyst switch
Catalyst 4500 series switches
Catalyst 5000 series switches
Catalyst 5500 series switches
Catalyst 6000 series switches
Catalyst 6500 series switches
Catalyst 4000 series switches
Switch software
CatOS system software
Error message
convert_post_SAC_CiscoMIB:Nvram block [#] unconvertible
