diff --git a/plugins/samplesource/filesource/filesourcegui.cpp b/plugins/samplesource/filesource/filesourcegui.cpp
index eb6509f58..45e7b8743 100644
--- a/plugins/samplesource/filesource/filesourcegui.cpp
+++ b/plugins/samplesource/filesource/filesourcegui.cpp
@@ -51,8 +51,7 @@ FileSourceGui::FileSourceGui(DeviceUISet *deviceUISet, QWidget* parent) :
 	m_samplesCount(0),
 	m_tickCount(0),
 	m_enableNavTime(false),
-	m_lastEngineState(DSPDeviceSourceEngine::StNotStarted),
-	m_accelerationMaxScale(1)
+	m_lastEngineState(DSPDeviceSourceEngine::StNotStarted)
 {
 	ui->setupUi(this);
 	ui->centerFrequency->setColorMapper(ColorMapper(ColorMapper::GrayGold));
@@ -164,9 +163,7 @@ bool FileSourceGui::handleMessage(const Message& message)
     {
         const FileSourceInput::MsgConfigureFileSource& cfg = (FileSourceInput::MsgConfigureFileSource&) message;
         m_settings = cfg.getSettings();
-        blockApplySettings(true);
         displaySettings();
-        blockApplySettings(false);
         return true;
     }
     else if (FileSourceInput::MsgReportFileSourceAcquisition::match(message))
@@ -237,12 +234,10 @@ void FileSourceGui::updateSampleRateAndFrequency()
 
 void FileSourceGui::displaySettings()
 {
-    ui->playLoop->blockSignals(true);
-    ui->acceleration->blockSignals(true);
+    blockApplySettings(true);
     ui->playLoop->setChecked(m_settings.m_loop);
     ui->acceleration->setCurrentIndex(FileSourceSettings::getAccelerationIndex(m_settings.m_accelerationFactor));
-    ui->acceleration->blockSignals(false);
-    ui->playLoop->blockSignals(false);
+    blockApplySettings(false);
 }
 
 void FileSourceGui::sendSettings()
@@ -251,9 +246,12 @@ void FileSourceGui::sendSettings()
 
 void FileSourceGui::on_playLoop_toggled(bool checked)
 {
-	m_settings.m_loop = checked;
-    FileSourceInput::MsgConfigureFileSource *message = FileSourceInput::MsgConfigureFileSource::create(m_settings);
-    m_sampleSource->getInputMessageQueue()->push(message);
+    if (m_doApplySettings)
+    {
+        m_settings.m_loop = checked;
+        FileSourceInput::MsgConfigureFileSource *message = FileSourceInput::MsgConfigureFileSource::create(m_settings);
+        m_sampleSource->getInputMessageQueue()->push(message);
+    }
 }
 
 void FileSourceGui::on_startStop_toggled(bool checked)
@@ -328,9 +326,12 @@ void FileSourceGui::on_showFileDialog_clicked(bool checked __attribute__((unused
 
 void FileSourceGui::on_acceleration_currentIndexChanged(int index)
 {
-    m_settings.m_accelerationFactor = FileSourceSettings::getAccelerationValue(index);
-    FileSourceInput::MsgConfigureFileSource *message = FileSourceInput::MsgConfigureFileSource::create(m_settings);
-    m_sampleSource->getInputMessageQueue()->push(message);
+    if (m_doApplySettings)
+    {
+        m_settings.m_accelerationFactor = FileSourceSettings::getAccelerationValue(index);
+        FileSourceInput::MsgConfigureFileSource *message = FileSourceInput::MsgConfigureFileSource::create(m_settings);
+        m_sampleSource->getInputMessageQueue()->push(message);
+    }
 }
 
 void FileSourceGui::configureFileName()
@@ -404,7 +405,7 @@ void FileSourceGui::setAccelerationCombo()
     ui->acceleration->clear();
     ui->acceleration->addItem(QString("1"));
 
-    for (unsigned int i = 0; i <= m_accelerationMaxScale; i++)
+    for (unsigned int i = 0; i <= FileSourceSettings::m_accelerationMaxScale; i++)
     {
         QString s;
         int m = pow(10.0, i);
diff --git a/plugins/samplesource/filesource/filesourcegui.h b/plugins/samplesource/filesource/filesourcegui.h
index 40ef0cf57..2e43c5b42 100644
--- a/plugins/samplesource/filesource/filesourcegui.h
+++ b/plugins/samplesource/filesource/filesourcegui.h
@@ -74,7 +74,6 @@ private:
     quint64 m_deviceCenterFrequency; //!< Center frequency in device
 	int m_lastEngineState;
 	MessageQueue m_inputMessageQueue;
-	unsigned int m_accelerationMaxScale;
 
 	void blockApplySettings(bool block) { m_doApplySettings = !block; }
 	void displaySettings();
diff --git a/plugins/samplesource/filesource/filesourceinput.cpp b/plugins/samplesource/filesource/filesourceinput.cpp
index c2fd15b29..43a4c803c 100644
--- a/plugins/samplesource/filesource/filesourceinput.cpp
+++ b/plugins/samplesource/filesource/filesourceinput.cpp
@@ -402,8 +402,11 @@ bool FileSourceInput::applySettings(const FileSourceSettings& settings, bool for
 
     if ((m_settings.m_accelerationFactor != settings.m_accelerationFactor) || force)
     {
-        QMutexLocker mutexLocker(&m_mutex);
-        m_fileSourceThread->setSampleRateAndSize(settings.m_accelerationFactor * m_sampleRate, m_sampleSize); // Fast Forward: 1 corresponds to live. 1/2 is half speed, 2 is double speed
+        if (m_fileSourceThread)
+        {
+            QMutexLocker mutexLocker(&m_mutex);
+            m_fileSourceThread->setSampleRateAndSize(settings.m_accelerationFactor * m_sampleRate, m_sampleSize); // Fast Forward: 1 corresponds to live. 1/2 is half speed, 2 is double speed
+        }
     }
 
     m_settings = settings;