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"%SW-VLAN-4-BAD-STARTUP-VLAN-CONFIG-FILE: Failed to configure VLAN from startup-config" error message received on catalyst 4000/4500 switch


Core issue

This error message is received when the supervisor module fails to create VLAN's

This condtion can occur when there is a VTP configuration issue.


The VLAN configuration is stored in the vlan.dat file. The vlan.dat file resides in nonvolatile memory. When the Supervisor module is replaced, vlan.dat is empty (0). On bootup, the switch compares the VTP domain name and VTP mode in the startup configuration file and the vlan.dat file. If the values do not match, the switch uses the configuration in the vlan.dat file. To perform a complete backup of your configuration, the vlan.dat file must be included in the backup along with the configuration.


VTP is a Layer 2 messaging protocol. VTP manages the addition, deletion, and rename of VLANs on a network-wide basis in order to maintain VLAN configuration consistency. VTP minimizes misconfigurations and configuration inconsistencies that can result in a number of problems. The problems include duplicate VLAN names, incorrect VLAN-type specifications, and security violations.

By default, the switch is in VTP server mode and is in the no-management domain state. These default settings change when the switch receives an advertisement for a domain over a trunk link or when a management domain is configured.

For more information kindly refer the following links,

Understanding VLAN Trunk Protocol (VTP)

VLAN Trunk Protocol part of Best Practices for Catalyst 6500/6000 Series and Catalyst 4500/4000 Series Switches Running Cisco IOS Software


The network administrator must upload both the vlan.dat file and the configuration file to restore the complete configuration.