diff --git a/src/Gui/TaskView/TaskImage.cpp b/src/Gui/TaskView/TaskImage.cpp
index 0480fd8aa1..1e2cbaf509 100644
--- a/src/Gui/TaskView/TaskImage.cpp
+++ b/src/Gui/TaskView/TaskImage.cpp
@@ -204,16 +204,20 @@ void TaskImage::scaleImage(double factor)
 
 void TaskImage::startScale()
 {
-    scale->activate();
-    ui->pushButtonScale->hide();
-    ui->groupBoxCalibration->show();
-    ui->pushButtonApply->setEnabled(false);
+    if (scale) {
+        scale->activate();
+        ui->pushButtonScale->hide();
+        ui->groupBoxCalibration->show();
+        ui->pushButtonApply->setEnabled(false);
+    }
 }
 
 void TaskImage::acceptScale()
 {
-    scaleImage(scale->getScaleFactor());
-    rejectScale();
+    if (scale) {
+        scaleImage(scale->getScaleFactor());
+        rejectScale();
+    }
 }
 
 void TaskImage::enableApplyBtn()
@@ -223,9 +227,11 @@ void TaskImage::enableApplyBtn()
 
 void TaskImage::rejectScale()
 {
-    scale->deactivate();
-    ui->pushButtonScale->show();
-    ui->groupBoxCalibration->hide();
+    if (scale) {
+        scale->deactivate();
+        ui->pushButtonScale->show();
+        ui->groupBoxCalibration->hide();
+    }
 }
 
 void TaskImage::onInteractiveScale()