this fixes https://github.com/gorhill/uBlock/issues/63

src/js/messaging.js

@@ -974,16 +974,19 @@ var getLocalData = function(callback) {
 /******************************************************************************/
 
 var backupUserData = function(callback) {
-    var onUserFiltersReady = function(details) {
     var userData = {
         timeStamp: Date.now(),
         version: vAPI.app.version,
         userSettings: µb.userSettings,
-            filterLists: µb.extractSelectedFilterLists(),
+        filterLists: {},
         netWhitelist: µb.stringFromWhitelist(µb.netWhitelist),
         dynamicFilteringString: µb.permanentFirewall.toString(),
-            userFilters: details.content
+        userFilters: ''
     };
+
+    var onSelectedListsReady = function(filterLists) {
+        userData.filterLists = filterLists;
+
         var now = new Date();
         var filename = vAPI.i18n('aboutBackupFilename')
             .replace('{{datetime}}', now.toLocaleString())
@@ -1001,6 +1004,12 @@ var backupUserData = function(callback) {
         getLocalData(callback);
     };
 
+    var onUserFiltersReady = function(details) {
+        userData.userFilters = details.content;
+        µb.extractSelectedFilterLists(onSelectedListsReady);
+    };
+
+
     µb.assets.get('assets/user/filters.txt', onUserFiltersReady);
 };
 
@@ -1050,7 +1059,7 @@ var restoreUserData = function(request) {
 /******************************************************************************/
 
 var resetUserData = function() {
-    vAPI.storage.clear(onAllRemoved);
+    vAPI.storage.clear();
 
     // Keep global counts, people can become quite attached to numbers
     µb.saveLocalSettings(true);

src/js/storage.js

@@ -102,19 +102,40 @@
 // This will remove all unused filter list entries from
 // µBlock.remoteBlacklists`. This helps reduce the size of backup files.
 
-µBlock.extractSelectedFilterLists = function() {
-    var r = JSON.parse(JSON.stringify(this.remoteBlacklists));
+µBlock.extractSelectedFilterLists = function(callback) {
+    var µb = this;
 
-    for ( var path in r ) {
-        if ( r.hasOwnProperty(path) === false ) {
+    var onBuiltinListsLoaded = function(details) {
+        var builtin;
+        try {
+            builtin = JSON.parse(details.content);
+        } catch (e) {
+            builtin = {};
+        }
+
+        var result = JSON.parse(JSON.stringify(µb.remoteBlacklists));
+        var builtinPath;
+        var defaultState;
+
+        for ( var path in result ) {
+            if ( result.hasOwnProperty(path) === false ) {
                 continue;
             }
-        if ( r[path].off !== false ) {
-            delete r[path];
+            builtinPath = path.replace(/^assets\/thirdparties\//, '');
+            defaultState = builtin.hasOwnProperty(builtinPath) === false ||
+                           builtin[builtinPath].off === true;
+            if ( result[path].off === true && result[path].off === defaultState ) {
+                delete result[path];
             }
         }
 
-    return r;
+        callback(result);
+    };
+
+    // https://github.com/gorhill/uBlock/issues/63
+    // Get built-in block lists: this will help us determine whether a
+    // specific list must be included in the result.
+    this.assets.get('assets/ublock/filter-lists.json', onBuiltinListsLoaded);
 };
 
 /******************************************************************************/