Uninstall the problem VIB using the following command - esxcli software vib remove -vibname="name of vib".List all installed VIBs to locate the name of the the problem VIB using the command - esxcli software vib list.Enable SSH on the Host and use Putty to connect.Load iLO to the Host and attach remote ISO.Ensure Host to be upgraded is in Maintenance Mode.If the VIB blocking the upgrade is linked to a critical network driver it can still be removed and the upgrade performed over the console \ iLO as you need not let host boot again after removal, the steps I took were.
#Vmware esxi 5 to 6 upgrade drivers
Having checked the problem VIB was nothing to do with any drivers used by the management NIC(s) I set about removing it.
![vmware esxi 5 to 6 upgrade vmware esxi 5 to 6 upgrade](http://www.vmwarearena.com/wp-content/uploads/2017/09/Difference-between-vSphere-6-vSphere-6.5.png)
![vmware esxi 5 to 6 upgrade vmware esxi 5 to 6 upgrade](https://d33wubrfki0l68.cloudfront.net/bac1d83d5d9043ed2392df9c618b99724ea7b8a8/1444f/wp-content/uploads/2015/08/upgrade-vmware-esxi-5.-to-6.0-part-1-interactive-upgrade-7.png)
The issue blocking the upgrade appeared to be with an incompatible VIB installed on the current 6.5 build. This gave further detail into the problem. The error thrown was pretty generic and did not give much away in the first instance, I then switched to the console on the host and attempted the upgrade by mounting the ESXi 6.7 iso through the HP iLO and booting from it. Using Update Manager within vCenter to deploy the custom HP 6.7u1 Build the following error was shown.
![vmware esxi 5 to 6 upgrade vmware esxi 5 to 6 upgrade](https://www.virtualizationhowto.com/wp-content/uploads/2021/03/creating-a-new-upgrade-baseline-for-vsphere-7.0-update-2.png)
Having just upgraded a VMware VCSA from 6.5 to 6.7u1 I set about uplifting the ESXi hosts only to stumble at the first hurdle.