In our company we deploy Thunderbird with WPKG. Every second or third release I extract the setup.exe, and do some changes in it. For example we set a sig_file for user, or set extensions like AddressbookSynchronizer and to make it automate we write into prefs.js a lots of line, like as " user_pref("mail.identity.id1.attach_signature", true); user_pref("mail.identity.id1.htmlSigFormat", false); user_pref("mail.identity.id1.reply_on_top", 1); user_pref("mail.identity.id1.sig_bottom", false); user_pref("mail.identity.id1.sig_file", "S:\\alairas.html"); user_pref("mail.identity.id1.sig_file-rel", "[ProfD]../../../../../../../../S:/alairas.html"); user_pref("mail.identity.id1.sig_on_fwd", true); " That is an example. So here comes the problem: In the 45.x.x release it is worked to set some changes for the user automatically, but in the 52.x.x release somehow it is not working. I attach a picture, where you can see the path where I always copy some files then I pack it back and create a customized setup.exe. So do you know, were there any changes in this settings? Please ask if you don't get is clearly. Thanks for the answers! See ya!