The Windows Installer Service could not be accessed.

There are a couple of reasons that might cause this. Check that your antivirus solution is not blocking some aspect of the install - especially custom actions which are often a cause of errors in the Vista environment. Check also (via task manager) to see if the msiexec process is not already doing something else.

When you try to trigger a repair, are you running with elevated rights?

Thanks for the ideas. I've checked and there's no antivirus on the failing machines. Msiexec isn't running prior to the repair. I'm logged in as Administrator (that's how our QA set up their machines) and starting the repair from the right-click menu in Control Panel "Programs & Features" and the log shows "Running product with elevated privileges."



I've found:



(1) the failed repair can be completed by running "Repair" a second time. This is consistent - one repair fails then the next "resumes" (according to the log) and completes. The log from a failed repair doesn't show anything special but stops at FileCopy action for CitrixAccelerator.exe (the resumed log is complete.)



(2) the problem seems to be a crash in the Windows Installer service (msiexec). The System Event Log shows: "The Windows Installer service terminated unexpectedly."



(3) the repair succeeds (i.e. first time through completes) after these steps:

- (a) stop the GUI (a monitor in the system tray)

- (b) net stop accelerator

- (c) net stop wandrivr

- (d) delete the file accelerator.exe



It feels like a permissions problem that's killing msiexec somehow - how can I finger it? It's new with Vista SP1.

If there was a permissions problem with msiexec, then all installs would barf. Have you had a look on the Citrix website in case this is a known issue with their code?

Have you tried running procmon during the repair to see what is going on under the covers?

Have you had a look in the application event log to see what sequence of events is taking place?

Try comparing event log entries and other test results with a system where the repair activity is successful.



By the way - on Vista, being logged in as Administrator does not automatically elevate your rights if UAC is turned on. You could try the same sequence with UAC turned off, and see if that changes anything.

Just updating this with current status. I think the problem is a broken Windows: the offending machines refuse to repair or update Windows Installer.

The problem only occurs on a couple of machines, can't reproduce it elsewhere. It's slow going because I only get access to those machines for about an hour per week, so each idea gets tried, fails, then there's another delay.

(2) the problem seems to be a crash in the Windows Installer service (msiexec). The System Event Log shows: "The Windows Installer service terminated unexpectedly."
If you enable crash dumps to be generated will there be one when this happens?