diff --git a/TBF/Rig/DataEntry/StandardCamera/TestStartEndForm.cs b/TBF/Rig/DataEntry/StandardCamera/TestStartEndForm.cs
index c54b3d4e2..ceb616aff 100644
--- a/TBF/Rig/DataEntry/StandardCamera/TestStartEndForm.cs
+++ b/TBF/Rig/DataEntry/StandardCamera/TestStartEndForm.cs
@@ -467,7 +467,7 @@ namespace TBF.Rig.DataEntry.StandardCamera
             {
                 for (int i = 0; i < WaterMetersCount; i++)
                 {
-                    double pulsesPerLtr = (regReaders != null && regReaders.Length > i) ? regReaders[i].PulsesPerLtr : 1;
+                    double pulsesPerLtr = (regReaders != null && regReaders.Length > i && regReaders[i] != null) ? regReaders[i].PulsesPerLtr : 1;
                     GetOcrParameters(pulsesPerLtr, out denominator, out format);
 
                     if ((mode == Tst.Start || mode == Tst.Both) && startTextBoxes[wm2phys[i + 1]].Enabled &&