diff --git a/util/psb_c_mmio_impl.f90 b/util/psb_c_mmio_impl.f90
index 62855d53..b30acf8d 100644
--- a/util/psb_c_mmio_impl.f90
+++ b/util/psb_c_mmio_impl.f90
@@ -217,7 +217,7 @@ subroutine mm_cvet2_write(b, header, info, iunit, filename)
   ncol = size(b,2) 
   write(outfile,*) nrow,ncol
 
-  write(frmtv,'(a,i5.5,a)') '(',2*ncol,'(es26.18,1x))'
+  write(frmtv,'(a,i0,a)') '(',2*ncol,'(es26.18,1x))'
 
   do i=1,size(b,1) 
     write(outfile,frmtv) b(i,1:ncol)
@@ -273,7 +273,7 @@ subroutine mm_cvet1_write(b, header, info, iunit, filename)
   ncol = 1
   write(outfile,*) nrow,ncol
 
-  write(frmtv,'(a,i5.5,a)') '(',2*ncol,'(es26.18,1x))'
+  write(frmtv,'(a,i0,a)') '(',2*ncol,'(es26.18,1x))'
 
   do i=1,size(b,1) 
     write(outfile,frmtv) b(i)
diff --git a/util/psb_d_mmio_impl.f90 b/util/psb_d_mmio_impl.f90
index 41caebc5..f912ed4a 100644
--- a/util/psb_d_mmio_impl.f90
+++ b/util/psb_d_mmio_impl.f90
@@ -210,7 +210,7 @@ subroutine mm_dvet2_write(b, header, info, iunit, filename)
   ncol = size(b,2) 
   write(outfile,*) nrow,ncol
 
-  write(frmtv,'(a,i3.3,a)') '(',ncol,'(es26.18,1x))'
+  write(frmtv,'(a,i0,a)') '(',ncol,'(es26.18,1x))'
 
   do i=1,size(b,1) 
     write(outfile,frmtv) b(i,1:ncol)
@@ -266,7 +266,7 @@ subroutine mm_dvet1_write(b, header, info, iunit, filename)
   ncol = 1
   write(outfile,*) nrow,ncol
 
-  write(frmtv,'(a,i3.3,a)') '(',ncol,'(es26.18,1x))'
+  write(frmtv,'(a,i0,a)') '(',ncol,'(es26.18,1x))'
 
   do i=1,size(b,1) 
     write(outfile,frmtv) b(i)
diff --git a/util/psb_s_mmio_impl.f90 b/util/psb_s_mmio_impl.f90
index 7b62ee1c..7085a207 100644
--- a/util/psb_s_mmio_impl.f90
+++ b/util/psb_s_mmio_impl.f90
@@ -212,7 +212,7 @@ subroutine mm_svet2_write(b, header, info, iunit, filename)
   ncol = size(b,2) 
   write(outfile,*) nrow,ncol
 
-  write(frmtv,'(a,i3.3,a)') '(',ncol,'(es26.18,1x))'
+  write(frmtv,'(a,i0,a)') '(',ncol,'(es26.18,1x))'
 
   do i=1,size(b,1) 
     write(outfile,frmtv) b(i,1:ncol)
@@ -268,7 +268,7 @@ subroutine mm_svet1_write(b, header, info, iunit, filename)
   ncol = 1
   write(outfile,*) nrow,ncol
 
-  write(frmtv,'(a,i3.3,a)') '(',ncol,'(es26.18,1x))'
+  write(frmtv,'(a,i0,a)') '(',ncol,'(es26.18,1x))'
 
   do i=1,size(b,1) 
     write(outfile,frmtv) b(i)
diff --git a/util/psb_z_mmio_impl.f90 b/util/psb_z_mmio_impl.f90
index adc87cb0..6b58a6f1 100644
--- a/util/psb_z_mmio_impl.f90
+++ b/util/psb_z_mmio_impl.f90
@@ -217,7 +217,7 @@ subroutine mm_zvet2_write(b, header, info, iunit, filename)
   ncol = size(b,2) 
   write(outfile,*) nrow,ncol
 
-  write(frmtv,'(a,i5.5,a)') '(',2*ncol,'(es26.18,1x))'
+  write(frmtv,'(a,i0,a)') '(',2*ncol,'(es26.18,1x))'
 
   do i=1,size(b,1) 
     write(outfile,frmtv) b(i,1:ncol)
@@ -273,7 +273,7 @@ subroutine mm_zvet1_write(b, header, info, iunit, filename)
   ncol = 1
   write(outfile,*) nrow,ncol
 
-  write(frmtv,'(a,i5.5,a)') '(',2*ncol,'(es26.18,1x))'
+  write(frmtv,'(a,i0,a)') '(',2*ncol,'(es26.18,1x))'
 
   do i=1,size(b,1) 
     write(outfile,frmtv) b(i)