Index: sources/cloudsync/CloudSyncController.cpp
===================================================================
diff -u -r7e503c5459ec77a2816d6c7789da9b206cedbe8a -rcd7956150072dcb5264c891ee363074623052ead
--- sources/cloudsync/CloudSyncController.cpp	(.../CloudSyncController.cpp)	(revision 7e503c5459ec77a2816d6c7789da9b206cedbe8a)
+++ sources/cloudsync/CloudSyncController.cpp	(.../CloudSyncController.cpp)	(revision cd7956150072dcb5264c891ee363074623052ead)
@@ -175,6 +175,10 @@
  */
 void CloudSyncController::onWatchFileChange(const QString &vFile)
 {
+    // TODO: It may improve the performance of the code to make it more specific.
+    //       Meaning, Device controller has only one file watcher and it will call all the slots of all the classes watching for a file change.
+    //       then ignore what is not important, but it may effect, the call queue and the threading performance.
+    //       Later investigation.
     if ( vFile != _date_out_File ) return; // ignore unwanted file updates.
     QString content;
     Storage::FileHandler::read(vFile, content);
@@ -622,7 +626,7 @@
 bool CloudSyncController::sendMessage(const Message &vMessage) {
     bool ok = false;
 
-    // this function is used int sendUIResponse, therefore the message IDs which are responses should be implemented here.
+    // this function is used in sendUIResponse, therefore the message IDs which are responses should be implemented here.
     switch (vMessage.id) {
     case eMessageID_DeviceRegister   :  /* No Request/Response */             break;
 
@@ -717,12 +721,25 @@
     if ( ok ) {
         for ( auto sourceFile : vMessage.params ) {
             QString fileName = QFileInfo(sourceFile).fileName();
+            // NOTE: If a file with the name newName already exists, copy() returns false (i.e., QFile will not overwrite it).
+            //       For the current scenario it is ideal, since that folder will turn RO after the successful registration and copying the files and reboot.
             if ( ! QFile::copy  (sourceFile, destination + fileName) )  { toLog(eError_CredentialCopy   , {fileName     }); ok = false; goto lOut; }
+            else {
+                // TODO: Registration should be atomic so it is all or nothing.
+                //       remove all the copied files.
+                //       it should be all or nothing
+                ok = false; goto lOut;
+            }
+        }
+        // if all the copies are successful then remove them.
+        for ( auto sourceFile : vMessage.params ) {
+            QString fileName = QFileInfo(sourceFile).fileName();
             if ( ! QFile::remove(sourceFile                        ) )  { toLog(eError_CredentialRemove , {fileName     }); ok = false; goto lOut; }
         }
     }
 
 lOut:
+    if ( ok ) sendCredentialsResponse();
     return ok;
 }
 
@@ -747,6 +764,19 @@
 }
 
 /*!
+ * \brief   CloudSyncController::sendCredentialsResponse
+ * \return  send the confirmation of the credential save on the device from UI to CS to let CS know when to delete them.
+ */
+bool CloudSyncController::sendCredentialsResponse()
+{
+    enum { eSucceed, eFailed };
+    bool ok = false;
+    qint32 messageID = UI2CS(eMessageID_CredentialsSave);
+    ok = sendUIBuff(QString("%1,1,%2").arg( messageID ).arg( ok ? eSucceed : eFailed ));
+    return ok;
+}
+
+/*!
  * \brief   CloudSyncController::sendTxCodeDisplay
  * \details reads the received Tx Code from CloudSync app and notifies with a signal.
  * \param   vMessage    : message containing the Tx Code.