Host Upgrade fails with “Cannot execute upgrade script on host”

I recently had the pleasue to time-warp a dinosaur upgrade an old ESXi 6.0 host to ESXi 6.7. Right after I triggered remediation with a current ESXi 6.7 iso image, I got an error message:

Cannot execute upgrade script on host

That message isn’t really specific. If you google it you’ll probably find a dozen possible reasons tor the failure. That can be:

None of the issues above did fit my observed problem. A good startpoint should be a look into vua.log on the affected host.

less /var/log/vua.log

Unfortunately that didn’t help either. So we had (again) a closer look at the VMware upgrade path matrix. A direct host upgrade from ESXi 6.0 to ESXi 6.7U3 is supported but while we re-checked the matrix our attention was drawn to a little footnote.

KB 76555 says there’s an issue with expired VIB certificates on hosts below a specific build numer.

  • ESXi 6.0 GA before build 9239799
  • ESXi 6.5 GA before build 8294253

In fact our ESXi host 6.0 had a build level of 7967664 (U3e) which is in the critical range. So we had to install some patches up to July 2018 (ESXi600-201807001). After that the upgrade to ESXI 6.7U3 went flawlessly.

What went wrong?

Of course we did check the matrix during the planning phase in early March 2020. That’s a standard operating procedure. Unfortunately something has changed in the meantime (the footnote was added). KB 76555 was updated in May 2020 and the issue affects upgrades to versions of ESXi 6.7 beyond April 28th 2020.

Take home message: Check your design and matrices again right before the projects starts.

VeeamON Tour 2020 Virtual Event

22. June 2020 9:30 – 13:30 CEST

The annual Veeam Roadshow will be held as Virtual Event this year.


  • New Veeam Availability Suite™ v10
  • Live-Stream and On-Demand-Content
  • Tecnical deep dive sessions by Veeam Systems Engineers
  • Information about Cloud as scalable and efficient backup target
  • Networking with other IT-Professionals and experts


  • Anton Gostev – Senior Vice President, Product Management
  • Danny Allan – CTO and SVP Product Strategy
  • Stefano Heisig – Senior Systems Engineer, DE
  • David Bewernick – Senior Systems Engineer, DE
  • Benedikt Däumling – Senior Systems Engineer, DE
  • Marco Horstmann – Senior Systems Engineer, DE
  • Stephan Herzig – Systems Engineer, CH
  • Herbert Szumovski – Systems Engineer, AT
  • Ivan Cioffi – Systems Engineer, CH
  • Andreas Lesslhumer – Systems Engineer, AT

VMUG GermanyVirtual Events 2020

Forced by the Corona Crisis we had to postpone our German VMUG UserCon 2020 to December 11th 2020. Meanwhile we’ll provide short bi-weekly virtual events. One hour, one speaker, one topic.

First speaker will be Niels Hagoort (VMware), co-author of Host Resources Deep Dive und Clustering Deep Dive.

You can join the Zoom session for free (VMUG registration required). online again

On Monday night we’ve encountered massive problems on the blog Page load was affected and visitors got an Internal Server Error 500.

We do apologize for the inconvenience.

Although it looked like an attack, the disturbance originated from a configuration issue that struck the website a couple of hours after the configuration change. Worse than that we’ve applied two changes which made troubleshooting even more difficult. The most likely suspect wasn’t the one that caused the problems.

Note to self: Careful with not-so-well known hosting functions! Do only change one parameter at a time. 😉