diff --git a/src/drivers/mct/main/seq_hist_mod.F90 b/src/drivers/mct/main/seq_hist_mod.F90
index 361bab2c90c..fb4ad4c7a5f 100644
--- a/src/drivers/mct/main/seq_hist_mod.F90
+++ b/src/drivers/mct/main/seq_hist_mod.F90
@@ -1150,7 +1150,7 @@ subroutine seq_hist_writeaux(infodata, EClock_d, comp, flow, aname, dname, &
                 yy = yy + yr_offset
              end if
              call shr_cal_ymdtod2string(date_str, yy, mm, dd)
-             write(hist_file(found), "(a6)") &
+             write(hist_file(found), "(6a)") &
                   trim(case_name),'.cpl.h',trim(aname),'.',trim(date_str), '.nc'
           else
              fk1 = 2