diff --git a/src/molearn/data/prepare.py b/src/molearn/data/prepare.py
index 8a43903..7b7252f 100644
--- a/src/molearn/data/prepare.py
+++ b/src/molearn/data/prepare.py
@@ -120,7 +120,7 @@ def read_traj(self) -> None:
             try:
                 # do not enforce topology file on this formats
                 fext = os.path.splitext(self.traj_path)[-1]
-                if any([fext == ".pdb", fext == "h5", fext == "lh5"]):
+                if any([fext == ".pdb", fext == ".h5", fext == ".lh5"]):
                     self.traj = md.load(self.traj_path)
                 else:
                     self.traj = md.load(self.traj_path, self.topo_path)
@@ -132,7 +132,8 @@ def read_traj(self) -> None:
         elif isinstance(self.traj_path, list):
             if isinstance(self.traj_path, list) and self.topo_path is None:
                 fext = os.path.splitext(self.traj_path[0])[-1]
-                if any([fext == ".pdb", fext == "h5", fext == "lh5"]):
+                # file type doesn't need a topo but zip needs equally long list
+                if any([fext == ".pdb", fext == ".h5", fext == ".lh5"]):
                     self.topo_path = [None] * len(self.traj_path)
             assert isinstance(
                 self.topo_path, list
@@ -144,12 +145,12 @@ def read_traj(self) -> None:
             top0 = None
             ucell0 = None
             for ct, (trp, top) in enumerate(zip(self.traj_path, self.topo_path)):
-                print(f"\tLoading Trajectory {ct}")
+                print(f"\tLoading {os.path.basename(trp)}")
                 loaded = None
                 try:
                     # do not enforce topology file on this formats
-                    trp_ext = os.path.splitext(trp)
-                    if any([trp_ext == ".pdb", trp_ext == "h5", trp_ext == "lh5"]):
+                    trp_ext = os.path.splitext(trp)[-1]
+                    if any([trp_ext == ".pdb", trp_ext == ".h5", trp_ext == ".lh5"]):
                         loaded = md.load(trp)
                     else:
                         loaded = md.load(trp, top)