Anyone who uses the Firefox browser will know that every so often, it automatically downloads an update and then installs it the next time the browser is run.
Well, the version on a client's Windows Terminal Services (WTS) server did precisely that. Trouble was, each time it started up it would try to install the update but report that an error had occurred. I scratched my head for a while (it wasn't a file permission thing as I was logged in as the admin user) but then decided I had more important things to do and left it alone.
This morning, I visited Netgear's Web site via Firefox on WTS to download a firmware update. As the navigation bar is a Flash thingy, I had to download the Flash player. But it wouldn't install the player because it kept complaining Firefox was still running.
Then the penny dropped. Someone else was logged in but not connected (you can do that in WTS - you suspend your session so you can come back to it later) with Firefox running. Log them out and hey presto - not only would Flash install, but so would the Firefox update.
Of course, I should have twigged this earlier, but it's a reminder that when you're doing any installation/config work on a multi-user machine, you need to remember that there might be ... errr ... multiple users!