After a recent power outage that lasted longer than my UPS runtime, I found that one of my ESXi hosts wasn’t online.
A quick look at the console screen showed that ESXi had attempted to boot and failed with Fatal error: 33 (Inconsistent data) when validating the file s.v00
I’ve had various boot media fail before, especially when using cheap USB sticks, but until now I hadn’t run into a file corruption issue.
As I was working remotely to the server I decided to just boot the latest ESXi install ISO I had available and select the “upgrade” process so that the host would retain its configuration.
This was actually a downgrade as the host was running 6.5 build 13004031 (Express Patch 13) but my install media was only 6.5 build 10719125 (Express Patch 11).
After the install had finished, I was able to boot the host successfully and then install the EP13 update to bring it back to the same build as the other hosts in the cluster.