(Solved) Problem with upgrading from ESXi 5.1 to 5.5 error “Cannot run upgrade script on host.”.

I was upgrading an ESXi 5.1 server via the update manager to version 5.5. I kept receiving following error during upgrade: “Cannot run upgrade script on host.” After seeing the error, the Host rebooted with version 5.1.

Exploration of the file/var/log/vua.log, showed me the following passage:


VUA exiting
Alert:WARNING: This application is not using QuickExit(). The exit code will be set to 0.@ bora/vim/lib/vmacore/main/service.cpp
--> Backtrace:
--> backtrace[00] rip Vmacore::System::Stacktrace::CaptureFullWork(unsigned int)
--> backtrace[01] rip Vmacore::System::SystemFactoryImpl::CreateBacktrace(Vmacore::Ref&)
--> backtrace[02] rip Vmacore::Service::Alert(char const*, char const*, int)
--> backtrace[03] rip Vmacore::Service::AppImpl::Init(Vmacore::Service::Config*)::do_quick_exit::invoke()
--> backtrace[04] rip /lib/libc.so.6
--> backtrace[05] rip /lib/libc.so.6
--> backtrace[06] rip /usr/share/vua/vua

Method 1: 

I fixed the problem by re-installing HA agents and then updating once more. This proved to be successful solution. 

Method 2: 

1. Disconnect Host from HA cluster
2. Delete/Switch off HA clusters (completely)
3. Execute the following command line on the Host:


cp /opt/vmware/uninstallers/VMware-fdm-uninstall.sh /tmp
chmod +x /tmp/VMware-fdm-uninstall.sh
/tmp/VMware-fdm-uninstall.sh

Above "Methods" resolves the issue.

Following link can be helpful for furthur details:
 http://virtualrealization.blogspot.ch/2013/12/vum-errror-during-remediation-of-esxi.html