SCCM 2012: update App-v package "The process cannot access the file because it is being used by another process"

Hi,

I sequenced SCCM 2012 console (R2) but it crashes.
Then I found this article: http://blog.naevette.com.au/2013/10/21/sequencing-sccm-2012-configuration-management-console-appv-5/ which tells me to change the _DeploymentConfig.xml

Tried that but SCCM won't let me update the sources.

It gives me

"The process cannot access the file '\\ourcompany\W7\Microsoft System Center 2012 R2 Console\1.0\.appv' because it is being used by another process."

Deploying App-v packages via sccm 2012 is new to us, we used to do this via App-v management server.
I'd like to know how to solve this issue and howto use the process properly, f.e. we update the package, want to try/test it first then put it into production. How do we do that without impacting production?

Please advise.
J.

Jan Hoedt