ENH: clearer error message if read_hdf loads upsupported HDF file (GH9539)

doc/source/whatsnew/v1.1.0.rst

@@ -98,6 +98,8 @@ Other enhancements
   This can be used to set a custom compression level, e.g.,
   ``df.to_csv(path, compression={'method': 'gzip', 'compresslevel': 1}``
   (:issue:`33196`)
+- :func:`pandas.read_hdf` has a more explicit error message when loading an
+  unsupported HDF file (:issue:`9539`)
 
 .. ---------------------------------------------------------------------------
 

pandas/io/pytables.py

@@ -387,7 +387,10 @@ def read_hdf(
         if key is None:
             groups = store.groups()
             if len(groups) == 0:
-                raise ValueError("No dataset in HDF5 file.")
+                raise ValueError(
+                    "Dataset that is either compatible with Pandas data types "
+                    "or is a table could not be found in HDF5 file."
+                )
             candidate_only_group = groups[0]
 
             # For the HDF file to have only one dataset, all other groups