A reader e-mailed me the other day about the KEEPCURRENTSETTINGS property of the App-V 4.5 client setup and how when used on the command line, other properties are ignored. I hadn’t seen this behaviour – or so I thought until I found that my client install script was not setting the right virtual driver letter or enabling streaming from file.

It turns out, I was using the KEEPCURRENTSETTINGS property, but I did have it set to 0 – just the existence of KEEPCURRENTSETTINGS was enabling Setup to ignore the other command line parameters.

Of course, this behaviour is documented, in the release notes, in this document: Application Virtualization Client Installer Command-Line Parameters, and there’s even a knowledgebase article dedicated to this parameter: Client installer command line parameters are ignored when used in conjunction with KEEPCURRENTSETTINGS=1 in Microsoft Application Virualization 4.5.

Having tested this, I would recommend avoiding the KEEPCURRENTSETTINGS if you can. Use a WMI filter to prevent Group Policy from applying to workstations until they are all running the 4.5 client.

Now if only I’d read those documents more closely I would have saved myself an hour of running around in circles. Sometimes it pays to RTFM..

(Thanks to Ment for helping out with this one)