diff --git a/src/com/google/android/gms/location/LocationClient.java b/src/com/google/android/gms/location/LocationClient.java
index 06b766d..04190ce 100644
--- a/src/com/google/android/gms/location/LocationClient.java
+++ b/src/com/google/android/gms/location/LocationClient.java
@@ -31,41 +31,49 @@ public class LocationClient extends AbstractPlayServicesClient {
     }
 
     public Location getLastLocation() {
+        assertConnected();
         return LocationServices.FusedLocationApi.getLastLocation(googleApiClient);
     }
 
     public PendingResult requestLocationUpdates(LocationRequest request,
             LocationListener listener) {
+        assertConnected();
         return LocationServices.FusedLocationApi.requestLocationUpdates(googleApiClient, request,
                 listener);
     }
 
     public PendingResult requestLocationUpdates(LocationRequest request,
             LocationListener listener, Looper looper) {
+        assertConnected();
         return LocationServices.FusedLocationApi.requestLocationUpdates(googleApiClient, request,
                 listener, looper);
     }
 
     public PendingResult requestLocationUpdates(LocationRequest request,
             PendingIntent callbackIntent) {
+        assertConnected();
         return LocationServices.FusedLocationApi.requestLocationUpdates(googleApiClient, request,
                 callbackIntent);
     }
 
     public PendingResult removeLocationUpdates(LocationListener listener) {
+        assertConnected();
         return LocationServices.FusedLocationApi.removeLocationUpdates(googleApiClient, listener);
     }
 
     public PendingResult removeLocationUpdates(PendingIntent callbackIntent) {
+        assertConnected();
         return LocationServices.FusedLocationApi.removeLocationUpdates(googleApiClient,
                 callbackIntent);
     }
 
     public PendingResult setMockMode(boolean isMockMode) {
+        assertConnected();
         return LocationServices.FusedLocationApi.setMockMode(googleApiClient, isMockMode);
     }
 
     public PendingResult setMockLocation(Location mockLocation) {
+        assertConnected();
         return LocationServices.FusedLocationApi.setMockLocation(googleApiClient, mockLocation);
     }
 }
diff --git a/src/org/microg/gms/common/GmsClient.java b/src/org/microg/gms/common/GmsClient.java
index 800b8df..80bf78c 100644
--- a/src/org/microg/gms/common/GmsClient.java
+++ b/src/org/microg/gms/common/GmsClient.java
@@ -43,7 +43,7 @@ public abstract class GmsClient<I extends IInterface> implements ApiConnection {
     private I serviceInterface;
 
     public GmsClient(Context context, GoogleApiClient.ConnectionCallbacks callbacks,
-            GoogleApiClient.OnConnectionFailedListener connectionFailedListener) {
+                     GoogleApiClient.OnConnectionFailedListener connectionFailedListener) {
         this.context = context;
         this.callbacks = callbacks;
         this.connectionFailedListener = connectionFailedListener;
@@ -57,9 +57,11 @@ public abstract class GmsClient<I extends IInterface> implements ApiConnection {
     protected abstract I interfaceFromBinder(IBinder binder);
 
     @Override
-    public void connect() {
+    public synchronized void connect() {
         Log.d(TAG, "connect()");
-        if (state == ConnectionState.CONNECTED || state == ConnectionState.CONNECTING) return;
+        if (state == ConnectionState.CONNECTED || state == ConnectionState.CONNECTING) {
+            Log.d(TAG, "Already connected/connecting - nothing to do");
+        }
         state = ConnectionState.CONNECTING;
         if (serviceConnection != null) {
             MultiConnectionKeeper.getInstance(context)
@@ -79,7 +81,7 @@ public abstract class GmsClient<I extends IInterface> implements ApiConnection {
     }
 
     @Override
-    public void disconnect() {
+    public synchronized void disconnect() {
         Log.d(TAG, "disconnect()");
         if (state == ConnectionState.DISCONNECTING) return;
         if (state == ConnectionState.CONNECTING) {
@@ -95,16 +97,16 @@ public abstract class GmsClient<I extends IInterface> implements ApiConnection {
     }
 
     @Override
-    public boolean isConnected() {
+    public synchronized boolean isConnected() {
         return state == ConnectionState.CONNECTED || state == ConnectionState.PSEUDO_CONNECTED;
     }
 
     @Override
-    public boolean isConnecting() {
+    public synchronized boolean isConnecting() {
         return state == ConnectionState.CONNECTING;
     }
 
-    public boolean hasError() {
+    public synchronized boolean hasError() {
         return state == ConnectionState.ERROR;
     }
 
@@ -112,7 +114,13 @@ public abstract class GmsClient<I extends IInterface> implements ApiConnection {
         return context;
     }
 
-    public I getServiceInterface() {
+    public synchronized I getServiceInterface() {
+        if (isConnecting()) {
+            // TODO: wait for connection to be established and return afterwards.
+            throw new IllegalStateException("Waiting for connection");
+        } else if (!isConnected()) {
+            throw new IllegalStateException("interface only available once connected!");
+        }
         return serviceInterface;
     }
 
@@ -135,7 +143,9 @@ public abstract class GmsClient<I extends IInterface> implements ApiConnection {
 
         @Override
         public void onServiceDisconnected(ComponentName componentName) {
-            state = ConnectionState.NOT_CONNECTED;
+            synchronized (GmsClient.this) {
+                state = ConnectionState.NOT_CONNECTED;
+            }
         }
     }
 
@@ -144,13 +154,15 @@ public abstract class GmsClient<I extends IInterface> implements ApiConnection {
         @Override
         public void onPostInitComplete(int statusCode, IBinder binder, Bundle params)
                 throws RemoteException {
-            if (state == ConnectionState.DISCONNECTING) {
+            synchronized (GmsClient.this) {
+                if (state == ConnectionState.DISCONNECTING) {
+                    state = ConnectionState.CONNECTED;
+                    disconnect();
+                    return;
+                }
                 state = ConnectionState.CONNECTED;
-                disconnect();
-                return;
+                serviceInterface = interfaceFromBinder(binder);
             }
-            state = ConnectionState.CONNECTED;
-            serviceInterface = interfaceFromBinder(binder);
             Log.d(TAG, "GmsCallbacks : onPostInitComplete(" + serviceInterface + ")");
             callbacks.onConnected(params);
         }
diff --git a/src/org/microg/gms/common/GmsConnector.java b/src/org/microg/gms/common/GmsConnector.java
index cd23afc..90712d9 100644
--- a/src/org/microg/gms/common/GmsConnector.java
+++ b/src/org/microg/gms/common/GmsConnector.java
@@ -64,7 +64,7 @@ public class GmsConnector<C extends ApiConnection, R extends Result, O extends A
 
         @Override
         public void handleMessage(Message msg) {
-            Log.d(TAG, "Handler : onClientAvailable");
+            Log.d(TAG, "Handler : handleMessage");
             AbstractPendingResult<R> result = (AbstractPendingResult<R>) msg.obj;
             try {
                 result.deliverResult(callback.onClientAvailable((C) apiClient.getApiConnection
diff --git a/src/org/microg/gms/common/api/AbstractPlayServicesClient.java b/src/org/microg/gms/common/api/AbstractPlayServicesClient.java
index 6ff1be4..0bd9814 100644
--- a/src/org/microg/gms/common/api/AbstractPlayServicesClient.java
+++ b/src/org/microg/gms/common/api/AbstractPlayServicesClient.java
@@ -30,6 +30,10 @@ public class AbstractPlayServicesClient implements GooglePlayServicesClient {
         this.googleApiClient = googleApiClient;
     }
 
+    public void assertConnected() {
+        if (!isConnected()) throw new IllegalStateException("Not connected!");
+    }
+
     @Override
     public void connect() {
         googleApiClient.connect();
diff --git a/src/org/microg/gms/common/api/GoogleApiClientImpl.java b/src/org/microg/gms/common/api/GoogleApiClientImpl.java
index ff2fa9c..1087861 100644
--- a/src/org/microg/gms/common/api/GoogleApiClientImpl.java
+++ b/src/org/microg/gms/common/api/GoogleApiClientImpl.java
@@ -120,8 +120,12 @@ public class GoogleApiClientImpl implements GoogleApiClient {
     }
 
     @Override
-    public void connect() {
+    public synchronized void connect() {
         Log.d(TAG, "connect()");
+        if (isConnected() || isConnecting()) {
+            Log.d(TAG, "Already connected/connecting, noting to do");
+            return;
+        }
         for (ApiConnection connection : apiConnections.values()) {
             if (!connection.isConnected()) {
                 connection.connect();
@@ -130,7 +134,7 @@ public class GoogleApiClientImpl implements GoogleApiClient {
     }
 
     @Override
-    public void disconnect() {
+    public synchronized void disconnect() {
         Log.d(TAG, "disconnect()");
         for (ApiConnection connection : apiConnections.values()) {
             if (connection.isConnected()) {
@@ -140,7 +144,7 @@ public class GoogleApiClientImpl implements GoogleApiClient {
     }
 
     @Override
-    public boolean isConnected() {
+    public synchronized boolean isConnected() {
         for (ApiConnection connection : apiConnections.values()) {
             if (!connection.isConnected()) return false;
         }
@@ -148,7 +152,7 @@ public class GoogleApiClientImpl implements GoogleApiClient {
     }
 
     @Override
-    public boolean isConnecting() {
+    public synchronized boolean isConnecting() {
         for (ApiConnection connection : apiConnections.values()) {
             if (connection.isConnecting()) return true;
         }
@@ -167,7 +171,7 @@ public class GoogleApiClientImpl implements GoogleApiClient {
     }
 
     @Override
-    public void reconnect() {
+    public synchronized void reconnect() {
         Log.d(TAG, "reconnect()");
         disconnect();
         connect();