diff --git a/src/qt/modaloverlay.cpp b/src/qt/modaloverlay.cpp
index a83f285034fdb..e32a0bdda8ebf 100644
--- a/src/qt/modaloverlay.cpp
+++ b/src/qt/modaloverlay.cpp
@@ -82,36 +82,38 @@ void ModalOverlay::tipUpdate(int count, const QDateTime& blockDate, double nVeri
     blockProcessTime.push_front(qMakePair(currentDate.toMSecsSinceEpoch(), nVerificationProgress));
 
     // show progress speed if we have more then one sample
-    if (blockProcessTime.size() >= 2)
-    {
-        double progressStart = blockProcessTime[0].second;
+    if (blockProcessTime.size() >= 2) {
         double progressDelta = 0;
         double progressPerHour = 0;
         qint64 timeDelta = 0;
         qint64 remainingMSecs = 0;
         double remainingProgress = 1.0 - nVerificationProgress;
-        for (int i = 1; i < blockProcessTime.size(); i++)
-        {
+        for (int i = 1; i < blockProcessTime.size(); i++) {
             QPair<qint64, double> sample = blockProcessTime[i];
 
             // take first sample after 500 seconds or last available one
             if (sample.first < (currentDate.toMSecsSinceEpoch() - 500 * 1000) || i == blockProcessTime.size() - 1) {
-                progressDelta = progressStart-sample.second;
+                progressDelta = blockProcessTime[0].second - sample.second;
                 timeDelta = blockProcessTime[0].first - sample.first;
-                progressPerHour = progressDelta/(double)timeDelta*1000*3600;
-                remainingMSecs = remainingProgress / progressDelta * timeDelta;
+                progressPerHour = progressDelta / (double) timeDelta * 1000 * 3600;
+                remainingMSecs = (progressDelta > 0) ? remainingProgress / progressDelta * timeDelta : -1;
                 break;
             }
         }
         // show progress increase per hour
-        ui->progressIncreasePerH->setText(QString::number(progressPerHour*100, 'f', 2)+"%");
+        ui->progressIncreasePerH->setText(QString::number(progressPerHour * 100, 'f', 2)+"%");
 
         // show expected remaining time
-        ui->expectedTimeLeft->setText(GUIUtil::formatNiceTimeOffset(remainingMSecs/1000.0));
+        if(remainingMSecs >= 0) {	
+            ui->expectedTimeLeft->setText(GUIUtil::formatNiceTimeOffset(remainingMSecs / 1000.0));
+        } else {
+            ui->expectedTimeLeft->setText(QObject::tr("unknown"));
+        }
 
         static const int MAX_SAMPLES = 5000;
-        if (blockProcessTime.count() > MAX_SAMPLES)
-            blockProcessTime.remove(MAX_SAMPLES, blockProcessTime.count()-MAX_SAMPLES);
+        if (blockProcessTime.count() > MAX_SAMPLES) {
+            blockProcessTime.remove(MAX_SAMPLES, blockProcessTime.count() - MAX_SAMPLES);
+        }
     }
 
     // show the last block date