diff --git a/mozilla/mailnews/mailnews.js b/mozilla/mailnews/mailnews.js
index e702abaa727..05c6f0118f6 100644
--- a/mozilla/mailnews/mailnews.js
+++ b/mozilla/mailnews/mailnews.js
@@ -116,6 +116,9 @@ pref("mailnews.wraplength",                 72);
 
 pref("mailnews.reply_on_top",               0); // 0=bottom 1=top 2=select+bottom 3=select+top
 
+pref("mail.purge_threshhold",                100);
+pref("mail.prompt_purge_threshhold",             false);   
+
 pref("mailnews.force_ascii_search",         false);
 pref("mailnews.autolookup_unknown_mime_types",  true);
 
diff --git a/mozilla/modules/libpref/src/init/mailnews.js b/mozilla/modules/libpref/src/init/mailnews.js
index e702abaa727..05c6f0118f6 100644
--- a/mozilla/modules/libpref/src/init/mailnews.js
+++ b/mozilla/modules/libpref/src/init/mailnews.js
@@ -116,6 +116,9 @@ pref("mailnews.wraplength",                 72);
 
 pref("mailnews.reply_on_top",               0); // 0=bottom 1=top 2=select+bottom 3=select+top
 
+pref("mail.purge_threshhold",                100);
+pref("mail.prompt_purge_threshhold",             false);   
+
 pref("mailnews.force_ascii_search",         false);
 pref("mailnews.autolookup_unknown_mime_types",  true);