diff --git a/system_setup/logon_script.sh b/system_setup/logon_script.sh
index 756d415..4851ecb 100755
--- a/system_setup/logon_script.sh
+++ b/system_setup/logon_script.sh
@@ -135,8 +135,15 @@ fi
 elog_add  ""
 
 #SYNC Firefox + Thunderbird Profile
-${SYSCONFIGPATH}/system_setup/mozilla_starter.sh firefox sync && ${SYSCONFIGPATH}/system_setup/mozilla_starter.sh thunderbird sync
-elog_add "Successfully synced Mozilla profiles (log in another file)."
+if [ ! -z "${PROFILE_FIREFOX_SRC}"]; then
+    ${SYSCONFIGPATH}/system_setup/mozilla_starter.sh firefox sync
+fi
+if [ $? -eq 0 ] && [ ! -z "${PROFILE_TB_SRC}"]; then
+    ${SYSCONFIGPATH}/system_setup/mozilla_starter.sh thunderbird sync
+    if [ $? -eq 0 ]; then
+        elog_add "Successfully synced Mozilla profiles (log in another file)."
+    fi
+fi
 
 elog_add "Sucessfully run logon script (Wait 3 seconds)"
 sleep 3