After I have upgraded my home lab from ESXi 7.0 to 7.0 update 1c (17325551) I ran into an issue updating VMware Tools on my VMs.

I tried both update options (“automatically” and “manually”), but both failed with a VIX error.

Automatilly update output = “vix error code = 21004”
Manually update = “vix error code = 21009”

Looking into to vmware.log file I saw this:

FILE:open error on /vmfs/volumes/5e941b5a-350761ee-750d-408d5caa1950/packages/vmtoolsRepo/vmtools/windows.iso: Operation not permitted

ToolsISO: Failed to open Tools ISO /vmfs/volumes/5e941b5a-350761ee-750d-408d5caa1950/packages/vmtoolsRepo/vmtools/windows.iso (FileIOResult=2).

Cannot open ISO image with upgrader binaries.

I tried to SSH into my ESXi host to check if the path to the windows.iso file was valid – it was! I even tried to copy to file to make sure it was readable. It was!

Then I decided to try to mount the windows.iso file manually (from the “edit settings” dialog on the VM)

This works! you can now update VMware Tools from inside the Windows guest OS.

Actually, if you mount the ISO manually on the VM you can also upgrade the Tools packages from VMware interface.

I have not been able to find the root cause for this issue, so just consider this as a workaround – feel free to comment below 🙂