Firefox 4 Beta - 'The operation can't be completed because the item "libsmime3.dylib" is in use.'

Spent a few minutes this morning saying "Argh" and "Gah!" in repeated succession whilst I struggled to install Firefox 4 Beta onto my Mac.

I kept seeing a big friendly dialogue box saying: -

'The operation can't be completed because the item "libsmime3.dylib" is in use.'

even though I'd shut down almost everything else.

I found a couple of useful posts, via Google, advising me to run this command: -

'sudo killall vpnagentd'

to kill the Cisco VPN client.

Sadly, it automatically relaunches each time you try :-(

I then found Matt Topper's blog which had the secret sauce :-)

So today I decided to switch over to the mainline Firefox 4.0 Beta from the Minefield dailies I've been using.  I started to copy the new Firefox.app directory over the existing one in my Applications folder and immediately was met with a:
'The operation can't be completed because the item "libsmime3.dylib" is in use.'
Well shit, whats holding onto that lib.  Turns out that it was my Cisco VPN Anywhere Agent, aka vpnagentd.  So I go ahead and do a:
'sudo killall vpnagentd'
Ugh and of course it restarts automatically before I can copy the files over.  So what now.  Oh yeah, it runs as a daemon so I need to use my old friend launchctl to unload it.  The command for this is:
sudo launchctl unload /Library/LaunchDaemons/com.cisco.anyconnect.vpnagentd.plist
w00t! Now the files copy over with no problem.  Now I need to put AnyConnect back into place.  This can be done with:
sudo launchctl load /Library/LaunchDaemons/com.cisco.anyconnect.vpnagentd.plist
That should do it, Firefox 4 Beta up online and working again.

So, following Matt's suggestion, I used the sudo launchctl command to unload the VPN client, installed the FF4 beta, and then again used sudo launchctl to re-enable VPN.

I'm now up and running with the loveliness that is Firefox 4 AND have a working Cisco VPN client :-)

Life is good ....