diff --git a/plugins/samplesource/filesource/filesourcegui.cpp b/plugins/samplesource/filesource/filesourcegui.cpp
index 688856ae5..c8e07638f 100644
--- a/plugins/samplesource/filesource/filesourcegui.cpp
+++ b/plugins/samplesource/filesource/filesourcegui.cpp
@@ -257,10 +257,10 @@ void FileSourceGui::updateWithStreamTime()
 	QString s_time = t.toString("hh:mm:ss");
 	ui->relTimeText->setText(s_timems);
 
-	quint64 startingTimeStampMsec = m_startingTimeStamp * 1000;
+    quint64 startingTimeStampMsec = (quint64) m_startingTimeStamp * 1000LL;
 	QDateTime dt = QDateTime::fromMSecsSinceEpoch(startingTimeStampMsec);
-	dt = dt.addSecs(t_sec);
-	dt = dt.addMSecs(t_msec);
+    dt = dt.addSecs((quint64) t_sec);
+    dt = dt.addMSecs((quint64) t_msec);
 	QString s_date = dt.toString("yyyy-MM-dd hh:mm:ss.zzz");
 	ui->absTimeText->setText(s_date);
 
diff --git a/plugins/samplesource/sdrdaemon/sdrdaemongui.cpp b/plugins/samplesource/sdrdaemon/sdrdaemongui.cpp
index 4eb963699..bae5edb37 100644
--- a/plugins/samplesource/sdrdaemon/sdrdaemongui.cpp
+++ b/plugins/samplesource/sdrdaemon/sdrdaemongui.cpp
@@ -331,9 +331,9 @@ void SDRdaemonGui::updateWithStreamData()
 
 void SDRdaemonGui::updateWithStreamTime()
 {
-	quint64 startingTimeStampMsec = (m_startingTimeStamp.tv_sec * 1000) + (m_startingTimeStamp.tv_usec / 1000);
-	QDateTime dt = QDateTime::fromMSecsSinceEpoch(startingTimeStampMsec);
-	QString s_date = dt.toString("yyyy-MM-dd  hh:mm:ss.zzz");
+    quint64 startingTimeStampMsec = ((quint64) m_startingTimeStamp.tv_sec * 1000LL) + ((quint64) m_startingTimeStamp.tv_usec / 1000LL);
+    QDateTime dt = QDateTime::fromMSecsSinceEpoch(startingTimeStampMsec);
+    QString s_date = dt.toString("yyyy-MM-dd  hh:mm:ss.zzz");
 	ui->absTimeText->setText(s_date);
 
 	if (m_syncLocked) {