diff --git a/config/preferences.json b/config/preferences.json
index 5c4919a..170948c 100644
--- a/config/preferences.json
+++ b/config/preferences.json
@@ -55,8 +55,8 @@
   "scanPlotDisabled" : false,
   "scanTableDisabled" : false,
   "cachedDataPanel" : false,
-  "dataExtensions" : null,
-  "dataSubFiles" : null,
+  "dataExtensions" : "",
+  "dataSubFiles" : "",
   "hideFileName" : false,
   "showEmergencyStop" : false,
   "showHomingButtons" : false,
@@ -71,13 +71,13 @@
   "defaultRendererColormap" : "Grayscale",
   "linePlot" : "ch.psi.pshell.plot.LinePlotJFree",
   "matrixPlot" : "ch.psi.pshell.plot.MatrixPlotJFree",
-  "surfacePlot" : null,
+  "surfacePlot" : "null",
   "timePlot" : "ch.psi.pshell.plot.TimePlotJFree",
   "plotsDetached" : false,
   "plotLayout" : "Vertical",
   "quality" : "High",
   "defaultPlotColormap" : "Temperature",
-  "markerSize" : 0,
+  "markerSize" : 2,
   "plotBackground" : null,
   "gridColor" : null,
   "outlineColor" : null,
@@ -119,5 +119,5 @@
     "deviceClassName" : "ch.psi.pshell.device.ReadonlyRegister$ReadonlyRegisterMatrix",
     "panelClassName" : "ch.psi.pshell.swing.DeviceValueChart"
   } ],
-  "scriptPopupDialog" : "None"
+  "scriptPopupDialog" : "Exception"
 }
\ No newline at end of file