diff --git a/SparkleLib/SparkleRepoBase.cs b/SparkleLib/SparkleRepoBase.cs
index 4be397e5..36d70a5c 100755
--- a/SparkleLib/SparkleRepoBase.cs
+++ b/SparkleLib/SparkleRepoBase.cs
@@ -523,7 +523,7 @@ namespace SparkleLib {
 
         public void DisableWatching ()
         {
-            lock (watch_lock) {
+            lock (this.watch_lock) {
                 this.watcher.EnableRaisingEvents = false;
                 this.local_timer.Stop ();
             }
@@ -532,7 +532,7 @@ namespace SparkleLib {
 
         public void EnableWatching ()
         {
-            lock (watch_lock) {
+            lock (this.watch_lock) {
                 this.watcher.EnableRaisingEvents = true;
                 this.local_timer.Start ();
             }
diff --git a/SparkleShare/SparkleControllerBase.cs b/SparkleShare/SparkleControllerBase.cs
index 4bd64c69..9b11c37f 100755
--- a/SparkleShare/SparkleControllerBase.cs
+++ b/SparkleShare/SparkleControllerBase.cs
@@ -85,6 +85,8 @@ namespace SparkleShare {
         private SparkleFetcherBase fetcher;
         private List<string> failed_avatars = new List<string> ();
 
+        private Object avatar_lock = new Object ();
+
 
         // Short alias for the translations
         public static string _ (string s)
@@ -920,7 +922,10 @@ namespace SparkleShare {
                     // if not empty
                     if (buffer.Length > 255) {
                         avatar_fetched = true;
-                        File.WriteAllBytes (avatar_file_path, buffer);
+
+                        lock (this.avatar_lock)
+                            File.WriteAllBytes (avatar_file_path, buffer);
+
                         SparkleHelpers.DebugInfo ("Controller", "Fetched gravatar for " + email);
                     }