diff --git a/core/modules/server/routes/get-tiddlers-json.js b/core/modules/server/routes/get-tiddlers-json.js
index 2c730e066..203900346 100644
--- a/core/modules/server/routes/get-tiddlers-json.js
+++ b/core/modules/server/routes/get-tiddlers-json.js
@@ -28,6 +28,9 @@ exports.handler = function(request,response,state) {
 			return;
 		}
 	}
+	if(state.wiki.getTiddlerText("$:/config/SyncSystemTiddlersFromServer") === "no") {
+		filter += "+[!is[system]]";
+	}
 	var excludeFields = (state.queryParameters.exclude || "text").split(","),
 		titles = state.wiki.filterTiddlers(filter);
 	response.writeHead(200, {"Content-Type": "application/json"});
diff --git a/core/modules/syncer.js b/core/modules/syncer.js
index 1ad9c3474..d5eae1f48 100644
--- a/core/modules/syncer.js
+++ b/core/modules/syncer.js
@@ -305,7 +305,8 @@ Syncer.prototype.syncFromServer = function() {
 				self.pollTimerId = null;
 				self.syncFromServer.call(self);
 			},self.pollTimerInterval);
-		};
+		},
+		syncSystemFromServer = (self.wiki.getTiddlerText("$:/config/SyncSystemTiddlersFromServer") === "yes" ? true : false);
 	if(this.syncadaptor && this.syncadaptor.getUpdatedTiddlers) {
 		this.logger.log("Retrieving updated tiddler list");
 		cancelNextSync();
@@ -320,9 +321,11 @@ Syncer.prototype.syncFromServer = function() {
 					self.titlesToBeLoaded[title] = true;
 				});
 				$tw.utils.each(updates.deletions,function(title) {
-					delete self.tiddlerInfo[title];
-					self.logger.log("Deleting tiddler missing from server:",title);
-					self.wiki.deleteTiddler(title);
+					if(syncSystemFromServer || !self.wiki.isSystemTiddler(title)) {
+						delete self.tiddlerInfo[title];
+						self.logger.log("Deleting tiddler missing from server:",title);
+						self.wiki.deleteTiddler(title);
+					}
 				});
 				if(updates.modifications.length > 0 || updates.deletions.length > 0) {
 					self.processTaskQueue();
@@ -365,9 +368,11 @@ Syncer.prototype.syncFromServer = function() {
 			}
 			// Delete any tiddlers that were previously reported but missing this time
 			$tw.utils.each(previousTitles,function(title) {
-				delete self.tiddlerInfo[title];
-				self.logger.log("Deleting tiddler missing from server:",title);
-				self.wiki.deleteTiddler(title);
+				if(syncSystemFromServer || !self.wiki.isSystemTiddler(title)) {
+					delete self.tiddlerInfo[title];
+					self.logger.log("Deleting tiddler missing from server:",title);
+					self.wiki.deleteTiddler(title);
+				}
 			});
 			self.processTaskQueue();
 		});
diff --git a/core/wiki/config/SyncFilter.tid b/core/wiki/config/SyncFilter.tid
index 41d71537c..06b3f192f 100644
--- a/core/wiki/config/SyncFilter.tid
+++ b/core/wiki/config/SyncFilter.tid
@@ -1,3 +1,3 @@
 title: $:/config/SyncFilter
 
-[is[tiddler]] -[[$:/core]] -[prefix[$:/StoryList]] -[prefix[$:/HistoryList]] -[status[pending]plugin-type[import]] -[[$:/isEncrypted]] -[prefix[$:/status/]] -[prefix[$:/state/]] -[prefix[$:/temp/]]
+[is[tiddler]] -[[$:/core]] -[[$:/library/sjcl.js]] -[prefix[$:/boot/]] -[prefix[$:/HistoryList]] -[status[pending]plugin-type[import]] -[[$:/isEncrypted]] -[prefix[$:/status/]] -[prefix[$:/state/]] -[prefix[$:/temp/]]
diff --git a/core/wiki/config/SyncSystemTiddlersFromServer.tid b/core/wiki/config/SyncSystemTiddlersFromServer.tid
new file mode 100644
index 000000000..32fcb7a46
--- /dev/null
+++ b/core/wiki/config/SyncSystemTiddlersFromServer.tid
@@ -0,0 +1,3 @@
+title: $:/config/SyncSystemTiddlersFromServer
+
+no
\ No newline at end of file