diff --git a/scripts/Diffraction/isis_powder/routines/common.py b/scripts/Diffraction/isis_powder/routines/common.py
index e25eaeb42fd4c90f20ef697b6f94529141311c0f..96e5195ee4afadd3ee981bfd94837595409fdeb4 100644
--- a/scripts/Diffraction/isis_powder/routines/common.py
+++ b/scripts/Diffraction/isis_powder/routines/common.py
@@ -43,7 +43,9 @@ def crop_banks_using_crop_list(bank_list, crop_values_list):
 
     # Finally check the number of elements are equal
     if len(bank_list) != len(crop_values_list):
-        raise RuntimeError("The number of TOF cropping values does not match the number of banks for this instrument")
+        raise RuntimeError("The number of TOF cropping values does not match the number of banks for this instrument.\n"
+                           "{} cropping windows were supplied for {} banks".format(len(crop_values_list), len(bank_list)
+                                                                                   ))
 
     output_list = []
     for spectra, cropping_values in zip(bank_list, crop_values_list):