Remediating Host with ESXi 6.5 VUM “The host returns esxupdate error code:15 error

The other day I was patching a couple of hosts on one of our environments. All worked out fine until I got one host that refused to update from vSphere ESXi 6.5 U1 to ESXi 6.5 U3. Throughout the day this host actually gave me loads of different errors. In …