Problem

Customers can install our product on Windows with a standard MSI package. To automate the installation administrators can use MSIEXEC and MSI parameters to configure our client.

A simple installation can look like this:

msiexec /qb /i "OneOffixx.msi" ... CACHEFOLDER="D:/OneOffixx/"

The “CACHEFOLDER” parameter will be written in the .exe.config file and our program will read it and stores offline content under the given location.

So far, so good.

For Terminal Server installations or “multi-user” scenarios this will not work, because each cache is bound to a local account. To solve this we could just insert the “%username%” enviroment variable, right?

Well… no… at least not with the obvious call, because this:

msiexec /qb /i "OneOffixx.msi" ... CACHEFOLDER="D:/%username%/OneOffixx/"

will result in a call like this:

msiexec /qb /i "OneOffixx.msi" ... CACHEFOLDER="D:/admin/OneOffixx/"

Solution

I needed a few hours and some Google-Fu to found the answer.

To “escape” those variables we need to invoke it like this:

msiexec /qb /i "OneOffixx.msi" ... CACHEFOLDER="D:/%%username%%/OneOffixx/"

Be aware: This stuff is a mess. It depends on your scenario. Checkout this Stackoverflow answer to learn more. The double percent did the trick for us, so I guess it is “ok-ish”.

Update

The above solution only works if you save the command in a file, e.g. in a install.bat file. If you want to invoke this in the CMD shell use this:

cmd /v /c msiexec /qb /i "OneOffixx.msi" ... CACHEFOLDER="%appdata%/OneOffixx"

The important parameter is “/v”, which enables delayed environment variable expansion.

Hope this helps!