diff --git a/pyfstat/core.py b/pyfstat/core.py
index 7ee28da37258a559b7e04b910e5a21ba00de3b93..0809f68afd21623683dd3813f97a8419e11a07cd 100755
--- a/pyfstat/core.py
+++ b/pyfstat/core.py
@@ -165,7 +165,10 @@ class BaseSearchClass(object):
         return thetas
 
     def _get_list_of_matching_sfts(self):
-        matches = [glob.glob(p) for p in self.sftfilepath]
+        # first make sure we have a list of paths, to avoid
+        # list comprehension trying to glob each single character
+        sftfilepathlist = np.atleast_1d(self.sftfilepath)
+        matches = [glob.glob(p) for p in sftfilepathlist]
         matches = [item for sublist in matches for item in sublist]
         if len(matches) > 0:
             return matches
diff --git a/pyfstat/grid_based_searches.py b/pyfstat/grid_based_searches.py
index 000d8add9e0ebc46fc0d3fd13df830d53b1a7b2a..f33f720a3be99f97ec81c6f0edcf2163675a26b0 100644
--- a/pyfstat/grid_based_searches.py
+++ b/pyfstat/grid_based_searches.py
@@ -106,6 +106,13 @@ class GridSearch(BaseSearchClass):
         if os.path.isfile(self.out_file) is False:
             logging.info('No old data found, continuing with grid search')
             return False
+        if self.sftfilepath is not None:
+            oldest_sft = min([os.path.getmtime(f) for f in
+                              self._get_list_of_matching_sfts()])
+            if os.path.getmtime(self.out_file) < oldest_sft:
+                logging.info('Search output data outdates sft files,'
+                             + ' continuing with grid search')
+                return False
         data = np.atleast_2d(np.genfromtxt(self.out_file, delimiter=' '))
         if np.all(data[:, 0:-1] == self.input_data):
             logging.info(