Index: sources/cloudsync/CloudSyncController.cpp
===================================================================
diff -u -rf68b226e67eb500758ee94fe015df48931240013 -r44550c670a421059754a70e2ce517e81f29c2e5d
--- sources/cloudsync/CloudSyncController.cpp	(.../CloudSyncController.cpp)	(revision f68b226e67eb500758ee94fe015df48931240013)
+++ sources/cloudsync/CloudSyncController.cpp	(.../CloudSyncController.cpp)	(revision 44550c670a421059754a70e2ce517e81f29c2e5d)
@@ -328,6 +328,7 @@
     case eError_CredentialEmpty : text = tr( "CS The credentials folder is empty."      ) ; break;
     case eError_TxCodeNoParam   : text = tr( "CS No Treatment Code provided."           ) ; break;
     case eError_TxCodeEmpty     : text = tr( "CS The provided Treatment Code is empty." ) ; break;
+    case eError_NotRegistered   : text = tr( "CS Not Sent, Device not registered."      ) ; break;
     }
     return text;
 }
@@ -369,6 +370,7 @@
     case eError_CredentialEmpty : info = QString( "[%1:%2]"     ).arg( vErrorID ).arg( item(0) )                ; break;
     case eError_TxCodeNoParam   : info = QString( "[%1:%2]"     ).arg( vErrorID ).arg( item(0) )                ; break;
     case eError_TxCodeEmpty     : info = QString( "[%1:%2]"     ).arg( vErrorID ).arg( item(0) )                ; break;
+    case eError_NotRegistered   : info = QString( "[%1:%2]"     ).arg( vErrorID ).arg( item(0) )                ; break;
     }
     return info;
 }
@@ -548,8 +550,10 @@
     QVariantList    args  ;
     Errors_Enum     error = eError_Unknown;
 
+    // only sends messages if device has been registered
     qint32 messageID = UI2CS(static_cast<MessageID_Enum>(vAction));
-    if ( ! _uiHistory.contains( messageID ) ) { error = eError_NoHistory; args = { messageID }; ok = false; goto lErr; }
+    if ( ! isRegistered() && vAction != eMessageID_DeviceRegister ) { error = eError_NotRegistered  ; args = { messageID }; ok = false; goto lErr; }
+    if ( ! _uiHistory.contains( messageID )                       ) { error = eError_NoHistory      ; args = { messageID }; ok = false; goto lErr; }
 
     sendUIBuff(makeUIBuff(messageID));
 
@@ -816,18 +820,28 @@
  */
 bool CloudSyncController::testDeviceRegister()
 {
-    QString         source      = QString(Storage::CloudSync_Base_Path_Name) + Storage::CloudSync_Credentials_Folder_Name;
-    qDebug() << source;
-    QFileInfoList   fileInfos   = QDir(source).entryInfoList(QDir::NoDotAndDotDot|QDir::Files);
-    if( fileInfos.isEmpty() ) {
         toLog(eError_CredentialEmpty,{}); // It is intentional that the vault folder path has not been sent to the log.
+        if( ! isRegistered() ) {
         sendDeviceRegister();
     }
 
     return true; // for now always true.
 }
 
 /*!
+ * \brief   CloudSyncController::isRegistered
+ * \details checks if the device is registered by looking for existing credentials.
+ * \return  true if device has been registered.
+ */
+bool CloudSyncController::isRegistered()
+{
+    QString         source      = QString(Storage::CloudSync_Base_Path_Name) + Storage::CloudSync_Credentials_Folder_Name;
+    qDebug() << source;
+    QFileInfoList   fileInfos   = QDir(source).entryInfoList(QDir::NoDotAndDotDot|QDir::Files);
+    return !fileInfos.isEmpty();
+}
+
+/*!
  * \brief   CloudSyncController::saveDeviceInfo
  * \details keeps the received device information and set a flag to wait for the next message.
  * \param   vAction - the action enum which identifies information source of HD or DG.
Index: sources/cloudsync/CloudSyncController.h
===================================================================
diff -u -r54c4136d95375116e6daf23b7d4179159cf13d0c -r44550c670a421059754a70e2ce517e81f29c2e5d
--- sources/cloudsync/CloudSyncController.h	(.../CloudSyncController.h)	(revision 54c4136d95375116e6daf23b7d4179159cf13d0c)
+++ sources/cloudsync/CloudSyncController.h	(.../CloudSyncController.h)	(revision 44550c670a421059754a70e2ce517e81f29c2e5d)
@@ -104,6 +104,8 @@
         eError_TxCodeEmpty      = 520, // the received Tx Code is empty
 
         eError_OutFileEmpty     = 521, // Out file has changed from CS2UI but the content is empty.
+
+        eError_NotRegistered    = 522, // avoid sending any message other than the device regitration, when device is not registered.
     };
 
     typedef QHash<qint32 , QStringList> MessageList;
@@ -239,6 +241,7 @@
     // device registration request
     bool sendDeviceRegister     (); // eMessageID_DeviceRegister
     bool testDeviceRegister     (); // eMessageID_DeviceRegister
+    bool isRegistered           ();
 
     // device state report
     bool saveDeviceState        (const QVariantList &vData);
Index: sources/model/dg/adjustment/settings/MAdjustDGSerialNumberResponse.cpp
===================================================================
diff -u -r27cc308ff5113a9386899d3c8f8b29962a8498e1 -r44550c670a421059754a70e2ce517e81f29c2e5d
--- sources/model/dg/adjustment/settings/MAdjustDGSerialNumberResponse.cpp	(.../MAdjustDGSerialNumberResponse.cpp)	(revision 27cc308ff5113a9386899d3c8f8b29962a8498e1)
+++ sources/model/dg/adjustment/settings/MAdjustDGSerialNumberResponse.cpp	(.../MAdjustDGSerialNumberResponse.cpp)	(revision 44550c670a421059754a70e2ce517e81f29c2e5d)
@@ -22,9 +22,37 @@
     };
 }
 
+/**
+ * \brief MAdjustSerialNumberDGResponse::isValid
+ * \details Checks if character meets DG serial constraints. (Alphanumeric or '-')
+ * \param vChar - the character.
+ * \return bool - whether character is valid.
+ */
+bool MAdjustSerialNumberDGResponse::isValid(const QChar &vChar)
+{
+    return vChar.isLetterOrNumber() || vChar == '-';
+}
+
+/**
+ * \brief MAdjustSerialNumberDGResponse::fromByteArray
+ * \details Removes any invalid characters from DG serial string.
+ * \param vByteArray - DG serial string represented as a byte array.
+ * \return true if serial contains any valid characters.
+ */
 bool MAdjustSerialNumberDGResponse::fromByteArray(const QByteArray &vByteArray, int *) {
-    _data.mSerialNumber = qPrintable(vByteArray);
-    return true;
+    // only keep valid characters from serial and stop if end of line reached
+    QString serial;
+    for ( char c: vByteArray ) {
+        if ( !c ) break;
+        QChar ch(c);
+        if ( isValid(ch) ) {
+            serial += ch;
+        }
+    }
+
+    // whitespace cannot be in serial and empty serial is invalid
+    _data.mSerialNumber = serial.trimmed();
+    return ! _data.mSerialNumber.isEmpty();
 }
 
 MAdjustSerialNumberDGResponse::Data MAdjustSerialNumberDGResponse::data() const {
Index: sources/model/dg/adjustment/settings/MAdjustDGSerialNumberResponse.h
===================================================================
diff -u -r27cc308ff5113a9386899d3c8f8b29962a8498e1 -r44550c670a421059754a70e2ce517e81f29c2e5d
--- sources/model/dg/adjustment/settings/MAdjustDGSerialNumberResponse.h	(.../MAdjustDGSerialNumberResponse.h)	(revision 27cc308ff5113a9386899d3c8f8b29962a8498e1)
+++ sources/model/dg/adjustment/settings/MAdjustDGSerialNumberResponse.h	(.../MAdjustDGSerialNumberResponse.h)	(revision 44550c670a421059754a70e2ce517e81f29c2e5d)
@@ -53,6 +53,7 @@
     friend class ::tst_models;
 
     QVariantList parameters() const override;
+    bool isValid(const QChar &vChar);
 
 public:
 
Index: sources/model/hd/adjustment/settings/MAdjustHDSerialNumberResponse.cpp
===================================================================
diff -u -r27cc308ff5113a9386899d3c8f8b29962a8498e1 -r44550c670a421059754a70e2ce517e81f29c2e5d
--- sources/model/hd/adjustment/settings/MAdjustHDSerialNumberResponse.cpp	(.../MAdjustHDSerialNumberResponse.cpp)	(revision 27cc308ff5113a9386899d3c8f8b29962a8498e1)
+++ sources/model/hd/adjustment/settings/MAdjustHDSerialNumberResponse.cpp	(.../MAdjustHDSerialNumberResponse.cpp)	(revision 44550c670a421059754a70e2ce517e81f29c2e5d)
@@ -22,9 +22,37 @@
     };
 }
 
+/**
+ * \brief MAdjustSerialNumberHDResponse::isValid
+ * \details Checks if character meets HD serial constraints. (alphanumeric or '-')
+ * \param vChar - the character.
+ * \return bool - whether character is valid.
+ */
+bool MAdjustSerialNumberHDResponse::isValid(const QChar &vChar)
+{
+    return vChar.isLetterOrNumber() || vChar == '-';
+}
+
+/**
+ * \brief MAdjustSerialNumberHDResponse::fromByteArray
+ * \details Removes any invalid characters from HD serial string.
+ * \param vByteArray - HD serial string represented as a byte array.
+ * \return bool - whether serial contains any valid characters.
+ */
 bool MAdjustSerialNumberHDResponse::fromByteArray(const QByteArray &vByteArray, int *) {
-    _data.mSerialNumber = qPrintable(vByteArray);
-    return true;
+    QString serial;
+    for ( char c: vByteArray ) {
+        // stop if end of file found while iterating through serial
+        if ( !c ) break;
+        QChar ch(c);
+        if ( isValid(ch) ) {
+            serial += ch;
+        }
+    }
+
+    // whitespace cannot be in serial and empty serial is invalid
+    _data.mSerialNumber = serial.trimmed();
+    return ! _data.mSerialNumber.isEmpty();
 }
 
 MAdjustSerialNumberHDResponse::Data MAdjustSerialNumberHDResponse::data() const {
Index: sources/model/hd/adjustment/settings/MAdjustHDSerialNumberResponse.h
===================================================================
diff -u -r27cc308ff5113a9386899d3c8f8b29962a8498e1 -r44550c670a421059754a70e2ce517e81f29c2e5d
--- sources/model/hd/adjustment/settings/MAdjustHDSerialNumberResponse.h	(.../MAdjustHDSerialNumberResponse.h)	(revision 27cc308ff5113a9386899d3c8f8b29962a8498e1)
+++ sources/model/hd/adjustment/settings/MAdjustHDSerialNumberResponse.h	(.../MAdjustHDSerialNumberResponse.h)	(revision 44550c670a421059754a70e2ce517e81f29c2e5d)
@@ -53,6 +53,7 @@
     friend class ::tst_models;
 
     QVariantList parameters() const override;
+    bool isValid(const QChar &vChar);
 
 public: