diff --git a/sources/evolution.F90 b/sources/evolution.F90
index 94a0d30..852212a 100644
--- a/sources/evolution.F90
+++ b/sources/evolution.F90
@@ -4205,15 +4205,23 @@ module evolution
 
     integer, intent(in) :: nh, nl
 
-    integer :: l, n, p
-    real(kind=8) :: fnorm, err
-
     type(block_data), pointer :: pdata
 
+    integer      :: l, n, p
+    real(kind=8) :: err
+
+    logical     , save :: first = .true.
+    real(kind=8), save :: fnorm = 1.0d+00
+
 !-------------------------------------------------------------------------------
 !
+    if (first) then
+      fnorm = 1.0d+00 / ncells**NDIMS
+
+      first = .false.
+    end if
+
     errors(:) = 0.0d+00
-    fnorm     = 1.0d+00 / (get_nleafs() * ncells**NDIMS)
 
     n = get_dblocks()
 
@@ -4233,7 +4241,7 @@ module evolution
                    abs(pdata%uu(p,nb:ne,nb:ne,  :  ,nl)))))**2)
 #endif /* NDIMS == 3 */
 !$omp atomic update
-        errors(p) = errors(p) + err
+        errors(p) = errors(p) + fnorm * err
       end do
     end do
 !$omp end parallel do
@@ -4242,7 +4250,7 @@ module evolution
     call reduce_sum(errors)
 #endif /* MPI */
 
-    errors(:) = sqrt(fnorm * errors(:))
+    errors(:) = sqrt(errors(:) / get_nleafs())
 
 !-------------------------------------------------------------------------------
 !
diff --git a/sources/io.F90 b/sources/io.F90
index 5e9928f..7fd905c 100644
--- a/sources/io.F90
+++ b/sources/io.F90
@@ -2420,7 +2420,8 @@ module io
                                                   'compressed_size', csize)
       allocate(buffer(csize))
 
-      open (newunit=io, file=file_path, access='stream', action='read')
+      open (newunit=io, file=file_path, access='stream', &
+                        status='old', action='read')
       read (io) buffer
       close (io)
 
@@ -2474,7 +2475,8 @@ module io
       end if
 
     else
-      open (newunit=io, file=file_path, access='stream', action='read')
+      open (newunit=io, file=file_path, access='stream', &
+                        status='old', action='read')
       read (io) array
       close (io)
     end if
@@ -2611,7 +2613,8 @@ module io
           filename = trim(array_file) // '.bin' // file_suffix
           filepath = trim(data_path) // trim(filename)
 
-          open (newunit=io, file=filepath, access='stream')
+          open (newunit=io, file=filepath, access='stream', &
+                            action='write', status='replace')
           write (io) buffer(1:cbytes)
           close (io)
 
@@ -2646,7 +2649,8 @@ module io
       filename = trim(array_file) // '.bin'
       filepath = trim(data_path) // trim(filename)
 
-      open (newunit=io, file=filepath, access='stream')
+      open (newunit=io, file=filepath, access='stream', &
+                        action='write', status='replace')
       write (io) array
       close (io)
 
@@ -5191,7 +5195,7 @@ module io
     write (fname, "('p',i6.6,'_',i5.5,'.xdmf')") isnap, nproc
     write (hname, "('p',i6.6,'_',i5.5,'.h5'  )") isnap, nproc
 
-    open (unit = xdmf, file = fname, status = 'replace')
+    open (unit=xdmf, file=fname, status='replace')
 
 ! write the header
 !
@@ -5379,7 +5383,7 @@ module io
 !
     write (fname, "('p',i6.6,'.xdmf')") isnap
 
-    open (unit = xdmf, file = fname, status = 'replace')
+    open (unit=xdmf, file=fname, status='replace')
 
 ! write the header
 !
diff --git a/sources/statistics.F90 b/sources/statistics.F90
index 722a38f..aa2b849 100644
--- a/sources/statistics.F90
+++ b/sources/statistics.F90
@@ -142,15 +142,15 @@ module statistics
       track_statistics = .false.
     end select
 
+    call get_parameter("statistics_interval", iintd)
+    iintd = max(1, iintd)
+
 ! only master process writes the files to the disk
 !
     if (master) then
 
 ! process parameters
 !
-      call get_parameter("statistics_interval", iintd)
-      iintd = max(1, iintd)
-
       stmp = "off"
       call get_parameter("statistics_append", stmp)
       select case(trim(stmp))