After a couple of try-and-error attempts, I was finally able to figure a way to get this sorted. It's maybe not very elegant, but working. Here's how in case someone with the same problem stumbles across this post: '''1) Download actual Firefox version from the net locally''' a) create a PowerShell script on your server - preferrably in a location designated for GPO files - with content: ''$client = new-object System.Net.WebClient $client.DownloadFile("https://download.mozilla.org/?product=firefox-msi-latest-ssl&os=win64&lang=de",".\firefox.msi")'' b) create a scheduled task to run this script daily '''2) Update workstations''' a) create a batch file - preferrably in the same location like the PowerShell script - with content: ''msiexec /i \\path\to\firefox.msi /qn'' b) create a GPO executing the batch file at the start of the computer (logon script won't work because admin credentials are needed for execution: Computer Configuration > Policies > Windows Settings > Scripts > Startup '''3) Update Terminal Server''' create a scheduled task to run daily - preferrably right after the download in 1) Programm: msiexec – arguments: /i \\[Servername]\Scripts\FirefoxUpdater\firefox.msi /qn – Start in: \\path\to\folder