diff --git a/airsonic-main/src/main/java/org/airsonic/player/domain/TransferStatus.java b/airsonic-main/src/main/java/org/airsonic/player/domain/TransferStatus.java
index ee58dcae..a21e6792 100644
--- a/airsonic-main/src/main/java/org/airsonic/player/domain/TransferStatus.java
+++ b/airsonic-main/src/main/java/org/airsonic/player/domain/TransferStatus.java
@@ -230,7 +230,7 @@ public class TransferStatus {
      *
      * @param active Whether this transfer is active.
      */
-    public void setActive(boolean active) {
+    public synchronized void setActive(boolean active) {
         this.active = active;
 
         if (active) {
diff --git a/airsonic-main/src/main/java/org/airsonic/player/service/SettingsService.java b/airsonic-main/src/main/java/org/airsonic/player/service/SettingsService.java
index 95e05e41..b74e4943 100644
--- a/airsonic-main/src/main/java/org/airsonic/player/service/SettingsService.java
+++ b/airsonic-main/src/main/java/org/airsonic/player/service/SettingsService.java
@@ -415,7 +415,7 @@ public class SettingsService {
         setProperty(KEY_PLAYLIST_FOLDER, playlistFolder);
     }
 
-    public String getMusicFileTypes() {
+    public synchronized String getMusicFileTypes() {
         return getProperty(KEY_MUSIC_FILE_TYPES, DEFAULT_MUSIC_FILE_TYPES);
     }
 
@@ -431,7 +431,7 @@ public class SettingsService {
         return cachedMusicFileTypesArray;
     }
 
-    public String getVideoFileTypes() {
+    public synchronized String getVideoFileTypes() {
         return getProperty(KEY_VIDEO_FILE_TYPES, DEFAULT_VIDEO_FILE_TYPES);
     }
 
@@ -447,7 +447,7 @@ public class SettingsService {
         return cachedVideoFileTypesArray;
     }
 
-    public String getCoverArtFileTypes() {
+    public synchronized String getCoverArtFileTypes() {
         return getProperty(KEY_COVER_ART_FILE_TYPES, DEFAULT_COVER_ART_FILE_TYPES);
     }