diff --git a/lib/filesystem.js b/lib/filesystem.js
index 972c01ef..2715e94c 100755
--- a/lib/filesystem.js
+++ b/lib/filesystem.js
@@ -214,6 +214,11 @@ function ReadTag(buffer, offset) {
 
 FS.prototype.OnJSONLoaded = function(fs)
 {
+    if(DEBUG)
+    {
+        console.assert(fs, "Invalid fs passed to OnJSONLoaded");
+    }
+
     //console.time("parse");
     var fsroot = JSON.parse(fs)["fsroot"];
     //console.timeEnd("parse");
@@ -344,19 +349,26 @@ FS.prototype.LoadFile = function(idx) {
     //    return;
     //}
 
-    LoadBinaryResource(this.baseurl + this.GetFullPath(inode.fid),  
-        function(buffer){
-            var data = this.inodedata[idx] = new Uint8Array(buffer);
-            inode.size = data.length; // correct size if the previous was wrong. 
-            inode.status = STATUS_OK;
-            //if (inode.name == "rcS") {
-            //    this.AppendDateHack(idx);
-            //}
-            this.filesinloadingqueue--;
-            this.HandleEvent(idx);            
-        }.bind(this), 
-        function(error){throw error;});
-
+    if(this.baseurl)
+    {
+        LoadBinaryResource(this.baseurl + this.GetFullPath(inode.fid),  
+            function(buffer){
+                var data = this.inodedata[idx] = new Uint8Array(buffer);
+                inode.size = data.length; // correct size if the previous was wrong. 
+                inode.status = STATUS_OK;
+                //if (inode.name == "rcS") {
+                //    this.AppendDateHack(idx);
+                //}
+                this.filesinloadingqueue--;
+                this.HandleEvent(idx);            
+            }.bind(this), 
+            function(error){throw error;});
+    }
+    else
+    {
+        // If baseurl is not set, we started with an empty filesystem. No files
+        // can be loaded
+    }
 }
 
 // -----------------------------------------------------
diff --git a/src/browser/starter.js b/src/browser/starter.js
index 5269be29..b8ff86bc 100644
--- a/src/browser/starter.js
+++ b/src/browser/starter.js
@@ -345,7 +345,7 @@ function V86Starter(options)
 
             setTimeout(function()
             {
-                if(settings.fs9p)
+                if(settings.fs9p && settings.fs9p_json)
                 {
                     settings.fs9p.OnJSONLoaded(settings.fs9p_json);
                 }