diff --git a/src/netcdf/netcdf.f90 b/src/netcdf/netcdf.f90
index a197ac944..717fdd188 100644
--- a/src/netcdf/netcdf.f90
+++ b/src/netcdf/netcdf.f90
@@ -354,7 +354,7 @@ module function netcdf_read_frame_base(self, iu, param) result(ierr)
                n = count(tpmask(:) .and. validmask(:))
             end select
 
-            do i = j, n
+            do j = 1, n
                idslot = ind(j)
    
                if (param%in_form == XV) then