diff --git a/crpptbx/TCV/gdat_tcv.m b/crpptbx/TCV/gdat_tcv.m
index 34c4b38e06ddb83ac6444a4f0f0a3a2cbdbd594f..26e0139e31775f7bb71add4cda385dd556d96ed5 100644
--- a/crpptbx/TCV/gdat_tcv.m
+++ b/crpptbx/TCV/gdat_tcv.m
@@ -849,7 +849,8 @@ elseif strcmp(mapping_for_tcv.method,'switchcase')
         rho(ir,:)= sqrt(1.-psiscatvol.data(:,ir)./psi_max.data(:))';
       end
     else
-      rho=NaN;
+      if gdat_params.nverbose>=1; warning(['psiscatvol empty?, no rho calculated for data_request = ' data_request_eff]); end
+      rho=[];
     end
     gdat_data.dim{1}=rho;
     gdat_data.dimunits=[{'sqrt(psi_norm)'} ; {'time [s]'}];