diff --git a/idefix/io.py b/idefix/io.py
index 55decc9..98f1fa4 100644
--- a/idefix/io.py
+++ b/idefix/io.py
@@ -143,6 +143,9 @@ def load_txt(fname, header, delimiter=' ', dtype=None):
     for i in ('x', 'y', 'z'):
         header_c.remove(i)
 
+    if not header_c:
+        return spatial
+
     log.debug('Create feature recarray')
     feature = raw_txt[header_c]
 
diff --git a/idefix/vxl.py b/idefix/vxl.py
index e5c7107..ff25bd6 100644
--- a/idefix/vxl.py
+++ b/idefix/vxl.py
@@ -237,7 +237,9 @@ def insight(grid, feature=None, method='density', mem_limit=None, verbose=False)
         print('\n'.join(lines))
 
     if mem_limit and mem_usage > mem_limit:
-        msg = 'The memory requirement is higher than allowed memory usage.'
+        msg = 'The memory requirement is higher than\
+               maximum authorized memory usage ({} GB needed).'.format(
+                       humanize.naturalsize(mem_usage, binary=True))
         log.error(msg)
         raise MemoryError(msg)
 
@@ -249,7 +251,7 @@ def _print_insight(grid, mem_usage, mem_limit):
     'Grid shape:     \t{}'.format([x.size - 1 for x in grid]),
     'Number of cells:\t{}'.format(humanize.intword(_bin_insight(grid))),
     'Predicted RAM usage:\t{}'.format(humanize.naturalsize(mem_usage, binary=True)),
-    'Allowed max RAM usage:\t{}'.format(humanize.naturalsize(mem_limit, binary=True) if mem_limit else 'Not set'),
+    'Max allowed RAM usage:\t{}'.format(humanize.naturalsize(mem_limit, binary=True) if mem_limit else 'Not set'),
     '--------------------',]
     return print_lines
 
@@ -326,7 +328,7 @@ def squash(voxel_grid, method='top', axis=-1):
     if method in ('top', 'center', 'bottom'):
         return _squash_position(voxel_grid, method, axis)
     elif method == 'count':
-        return ~voxel_grid.mask.sum(axis=axis)
+        return np.sum(~voxel_grid.mask, axis=axis)
     elif method == 'mean':
         return voxel_grid.mean(axis=axis)
     elif method == 'median':