ESXi 6.5 Host Crash then Guest Fails to Power On

I ran into a situation where the host had crashed because of a driver problem (vmw_ahci). After changing the driver and rebooting the host, one of the guest VMs then failed to power on with the following errors:

  • File system specific implementation of LookupAndOpen[file] failed
  • Object type requires hosted I/O
  • Cannot open the disk ‘…vmdk’ or one of the snapshot disks it depends on.
  • Module ‘Disk’ power on failed.
  • Failed to start the virtual machine.

The solution was to repair the disk using vmkfstools. This particular VM was split into two files, vmname.vmdk and vmname-s001.vmdk. You will want to perform the commands on the primary (pointer) vmdk (not vmname-s###.vmdk).
From the ESXi console, issue the following command substituting your actual path:

In this case vmkfstools reported that the disk should be repaired. It would be prudent at this point to back up your vmdk files before trying the repair. Then initiate the repair on the primary vmdk with:

Once you get a notification that the repair has completed, try to start your VM again.