diff --git a/src/com/owncloud/android/files/services/FileDownloader.java b/src/com/owncloud/android/files/services/FileDownloader.java
index b6f21a5cb0..513a639f24 100644
--- a/src/com/owncloud/android/files/services/FileDownloader.java
+++ b/src/com/owncloud/android/files/services/FileDownloader.java
@@ -174,10 +174,11 @@ public class FileDownloader extends Service
                 Pair<String, String> putResult = mPendingDownloads.putIfAbsent(
                         account, file.getRemotePath(), newDownload
                 );
-                String downloadKey = putResult.first;
-                requestedDownloads.add(downloadKey);
-
-                sendBroadcastNewDownload(newDownload, putResult.second);
+                if (putResult != null) {
+                    String downloadKey = putResult.first;
+                    requestedDownloads.add(downloadKey);
+                    sendBroadcastNewDownload(newDownload, putResult.second);
+                }   // else, file already in the queue of downloads; don't repeat the request
 
             } catch (IllegalArgumentException e) {
                 Log_OC.e(TAG, "Not enough information provided in intent: " + e.getMessage());
diff --git a/src/com/owncloud/android/files/services/FileUploader.java b/src/com/owncloud/android/files/services/FileUploader.java
index df4dccdac0..89dc8b8553 100644
--- a/src/com/owncloud/android/files/services/FileUploader.java
+++ b/src/com/owncloud/android/files/services/FileUploader.java
@@ -300,8 +300,10 @@ public class FileUploader extends Service
                 Pair<String, String> putResult = mPendingUploads.putIfAbsent(
                         account, files[i].getRemotePath(), newUpload
                 );
-                uploadKey = putResult.first;
-                requestedUploads.add(uploadKey);
+                if (putResult != null) {
+                    uploadKey = putResult.first;
+                    requestedUploads.add(uploadKey);
+                }   // else, file already in the queue of uploads; don't repeat the request
             }
 
         } catch (IllegalArgumentException e) {
diff --git a/src/com/owncloud/android/files/services/IndexedForest.java b/src/com/owncloud/android/files/services/IndexedForest.java
index 4c1ac7bd25..8f4ccb67c0 100644
--- a/src/com/owncloud/android/files/services/IndexedForest.java
+++ b/src/com/owncloud/android/files/services/IndexedForest.java
@@ -101,38 +101,45 @@ public class IndexedForest<V> {
     public /* synchronized */ Pair<String, String> putIfAbsent(Account account, String remotePath, V value) {
         String targetKey = buildKey(account, remotePath);
         Node<V> valuedNode = new Node(targetKey, value);
-        mMap.putIfAbsent(
-                targetKey,
-                valuedNode
+        Node<V> previousValue = mMap.putIfAbsent(
+            targetKey,
+            valuedNode
         );
+        if (previousValue != null) {
+            // remotePath already known; not replaced
+            return null;
 
-        String currentPath = remotePath, parentPath = null, parentKey = null;
-        Node<V> currentNode = valuedNode, parentNode = null;
-        boolean linked = false;
-        while (!OCFile.ROOT_PATH.equals(currentPath) && !linked) {
-            parentPath = new File(currentPath).getParent();
-            if (!parentPath.endsWith(OCFile.PATH_SEPARATOR)) {
-                parentPath += OCFile.PATH_SEPARATOR;
+        } else {
+            // value really added
+            String currentPath = remotePath, parentPath = null, parentKey = null;
+            Node<V> currentNode = valuedNode, parentNode = null;
+            boolean linked = false;
+            while (!OCFile.ROOT_PATH.equals(currentPath) && !linked) {
+                parentPath = new File(currentPath).getParent();
+                if (!parentPath.endsWith(OCFile.PATH_SEPARATOR)) {
+                    parentPath += OCFile.PATH_SEPARATOR;
+                }
+                parentKey = buildKey(account, parentPath);
+                parentNode = mMap.get(parentKey);
+                if (parentNode == null) {
+                    parentNode = new Node(parentKey, null);
+                    parentNode.addChild(currentNode);
+                    mMap.put(parentKey, parentNode);
+                } else {
+                    parentNode.addChild(currentNode);
+                    linked = true;
+                }
+                currentPath = parentPath;
+                currentNode = parentNode;
             }
-            parentKey = buildKey(account, parentPath);
-            parentNode = mMap.get(parentKey);
-            if (parentNode == null) {
-                parentNode = new Node(parentKey, null);
-                parentNode.addChild(currentNode);
-                mMap.put(parentKey, parentNode);
-            } else {
-                parentNode.addChild(currentNode);
-                linked = true;
-            }
-            currentPath = parentPath;
-            currentNode = parentNode;
-        }
 
-        String linkedTo = OCFile.ROOT_PATH;
-        if (linked) {
-            linkedTo = parentNode.getKey().substring(account.name.length());
+            String linkedTo = OCFile.ROOT_PATH;
+            if (linked) {
+                linkedTo = parentNode.getKey().substring(account.name.length());
+            }
+
+            return new Pair<String, String>(targetKey, linkedTo);
         }
-        return new Pair<String, String>(targetKey, linkedTo);
     };
 
 
diff --git a/src/com/owncloud/android/services/SyncFolderHandler.java b/src/com/owncloud/android/services/SyncFolderHandler.java
index 33318f5712..daa16128d1 100644
--- a/src/com/owncloud/android/services/SyncFolderHandler.java
+++ b/src/com/owncloud/android/services/SyncFolderHandler.java
@@ -138,8 +138,11 @@ class SyncFolderHandler extends Handler {
 
     public void add(Account account, String remotePath,
                     SynchronizeFolderOperation syncFolderOperation){
-        mPendingOperations.putIfAbsent(account, remotePath, syncFolderOperation);
-        sendBroadcastNewSyncFolder(account, remotePath);    // TODO upgrade!
+        Pair<String, String> putResult =
+                mPendingOperations.putIfAbsent(account, remotePath, syncFolderOperation);
+        if (putResult != null) {
+            sendBroadcastNewSyncFolder(account, remotePath);    // TODO upgrade!
+        }
     }
 
 
diff --git a/src/com/owncloud/android/ui/activity/FileDisplayActivity.java b/src/com/owncloud/android/ui/activity/FileDisplayActivity.java
index e814c2d3bd..697d7b3ec1 100644
--- a/src/com/owncloud/android/ui/activity/FileDisplayActivity.java
+++ b/src/com/owncloud/android/ui/activity/FileDisplayActivity.java
@@ -1047,7 +1047,7 @@ public class FileDisplayActivity extends HookActivity
         @Override
         public void onReceive(Context context, Intent intent) {
             try {
-                String uploadedRemotePath = intent.getStringExtra(FileDownloader.EXTRA_REMOTE_PATH);
+                String uploadedRemotePath = intent.getStringExtra(FileUploader.EXTRA_REMOTE_PATH);
                 String accountName = intent.getStringExtra(FileUploader.ACCOUNT_NAME);
                 boolean sameAccount = getAccount() != null && accountName.equals(getAccount().name);
                 OCFile currentDir = getCurrentDir();
@@ -1056,7 +1056,7 @@ public class FileDisplayActivity extends HookActivity
 
                 if (sameAccount && isDescendant) {
                     String linkedToRemotePath =
-                            intent.getStringExtra(FileDownloader.EXTRA_LINKED_TO_PATH);
+                            intent.getStringExtra(FileUploader.EXTRA_LINKED_TO_PATH);
                     if (linkedToRemotePath == null || isAscendant(linkedToRemotePath)) {
                         refreshListOfFilesFragment();
                     }