diff --git a/lib/spack/llnl/util/filesystem.py b/lib/spack/llnl/util/filesystem.py
index 5ed4d9249a..56b96b3a32 100644
--- a/lib/spack/llnl/util/filesystem.py
+++ b/lib/spack/llnl/util/filesystem.py
@@ -130,7 +130,7 @@ def groupid_to_group(x):
         try:
             for line in fileinput.input(filename, inplace=True):
                 print(re.sub(regex, repl, line.rstrip('\n')))
-        except:
+        except BaseException:
             # clean up the original file on failure.
             shutil.move(backup_filename, filename)
             raise
diff --git a/lib/spack/llnl/util/tty/__init__.py b/lib/spack/llnl/util/tty/__init__.py
index ac51d201aa..5668f73388 100644
--- a/lib/spack/llnl/util/tty/__init__.py
+++ b/lib/spack/llnl/util/tty/__init__.py
@@ -250,7 +250,7 @@ def ioctl_GWINSZ(fd):
         try:
             rc = struct.unpack('hh', fcntl.ioctl(
                 fd, termios.TIOCGWINSZ, '1234'))
-        except:
+        except BaseException:
             return
         return rc
     rc = ioctl_GWINSZ(0) or ioctl_GWINSZ(1) or ioctl_GWINSZ(2)
@@ -259,7 +259,7 @@ def ioctl_GWINSZ(fd):
             fd = os.open(os.ctermid(), os.O_RDONLY)
             rc = ioctl_GWINSZ(fd)
             os.close(fd)
-        except:
+        except BaseException:
             pass
     if not rc:
         rc = (os.environ.get('LINES', 25), os.environ.get('COLUMNS', 80))
diff --git a/lib/spack/llnl/util/tty/colify.py b/lib/spack/llnl/util/tty/colify.py
index b04775b4f1..c70d796955 100644
--- a/lib/spack/llnl/util/tty/colify.py
+++ b/lib/spack/llnl/util/tty/colify.py
@@ -167,7 +167,7 @@ def colify(elts, **options):
             r, c = env_size.split('x')
             console_rows, console_cols = int(r), int(c)
             tty = True
-        except:
+        except BaseException:
             pass
 
     # Use only one column if not a tty.
diff --git a/lib/spack/llnl/util/tty/log.py b/lib/spack/llnl/util/tty/log.py
index 02084cc382..e8f3ce4d57 100644
--- a/lib/spack/llnl/util/tty/log.py
+++ b/lib/spack/llnl/util/tty/log.py
@@ -166,7 +166,7 @@ def _file_descriptors_work(*streams):
         for stream in streams:
             stream.fileno()
         return True
-    except:
+    except BaseException:
         return False
 
 
@@ -310,7 +310,7 @@ def __enter__(self):
             # need to pass this b/c multiprocessing closes stdin in child.
             try:
                 input_stream = os.fdopen(os.dup(sys.stdin.fileno()))
-            except:
+            except BaseException:
                 input_stream = None  # just don't forward input if this fails
 
             self.process = multiprocessing.Process(
@@ -483,7 +483,7 @@ def _writer_daemon(self, stdin):
                             force_echo = True
                         if xoff in controls:
                             force_echo = False
-        except:
+        except BaseException:
             tty.error("Exception occurred in writer daemon!")
             traceback.print_exc()
 
diff --git a/lib/spack/spack/build_environment.py b/lib/spack/spack/build_environment.py
index cc03374769..aac1d38f5a 100644
--- a/lib/spack/spack/build_environment.py
+++ b/lib/spack/spack/build_environment.py
@@ -567,7 +567,7 @@ def child_process(child_pipe, input_stream):
             tty.msg(e.message)
             child_pipe.send(None)
 
-        except:
+        except BaseException:
             # catch ANYTHING that goes wrong in the child process
             exc_type, exc, tb = sys.exc_info()
 
diff --git a/lib/spack/spack/cmd/create.py b/lib/spack/spack/cmd/create.py
index d38f11f63b..d0c6c37e29 100644
--- a/lib/spack/spack/cmd/create.py
+++ b/lib/spack/spack/cmd/create.py
@@ -34,7 +34,7 @@
 from llnl.util.filesystem import mkdirp
 from spack.repository import Repo
 from spack.spec import Spec
-from spack.util.executable import which
+from spack.util.executable import which, ProcessError
 from spack.util.naming import mod_to_class
 from spack.util.naming import simplify_name, valid_fully_qualified_module_name
 from spack.url import UndetectableNameError, UndetectableVersionError
@@ -471,14 +471,14 @@ def __call__(self, stage, url):
             try:
                 unzip  = which('unzip')
                 output = unzip('-lq', stage.archive_file, output=str)
-            except:
+            except ProcessError:
                 output = ''
         else:
             try:
                 tar    = which('tar')
                 output = tar('--exclude=*/*/*', '-tf',
                              stage.archive_file, output=str)
-            except:
+            except ProcessError:
                 output = ''
         lines = output.split('\n')
 
diff --git a/lib/spack/spack/cmd/install.py b/lib/spack/spack/cmd/install.py
index d4a59c9e8f..7c014e0a92 100644
--- a/lib/spack/spack/cmd/install.py
+++ b/lib/spack/spack/cmd/install.py
@@ -286,7 +286,7 @@ def wrapper(self, *args, ** kwargs):
                     message='Unexpected exception thrown during install',
                     text=text
                 )
-            except:
+            except BaseException:
                 # Anything else is also an error
                 duration = time.time() - start_time
                 test_case.set_duration(duration)
diff --git a/lib/spack/spack/database.py b/lib/spack/spack/database.py
index 46e8a5ae2e..91142579d5 100644
--- a/lib/spack/spack/database.py
+++ b/lib/spack/spack/database.py
@@ -491,7 +491,7 @@ def _read_suppress_error():
 
                 self._check_ref_counts()
 
-            except:
+            except BaseException:
                 # If anything explodes, restore old data, skip write.
                 self._data = old_data
                 raise
@@ -544,7 +544,7 @@ def _write(self, type, value, traceback):
             with open(temp_file, 'w') as f:
                 self._write_to_file(f)
             os.rename(temp_file, self._index_path)
-        except:
+        except BaseException:
             # Clean up temp file if something goes wrong.
             if os.path.exists(temp_file):
                 os.remove(temp_file)
diff --git a/lib/spack/spack/fetch_strategy.py b/lib/spack/spack/fetch_strategy.py
index 4ab76c8d2a..9aa6b9afd1 100644
--- a/lib/spack/spack/fetch_strategy.py
+++ b/lib/spack/spack/fetch_strategy.py
@@ -970,7 +970,7 @@ def from_list_url(pkg):
             except KeyError:
                 tty.msg("Can not find version %s in url_list" %
                         pkg.version)
-        except:
+        except BaseException:
             tty.msg("Could not determine url from list_url.")
 
 
diff --git a/lib/spack/spack/main.py b/lib/spack/spack/main.py
index 775873df23..646969859a 100644
--- a/lib/spack/spack/main.py
+++ b/lib/spack/spack/main.py
@@ -410,8 +410,8 @@ def __call__(self, *argv, **kwargs):
         except SystemExit as e:
             self.returncode = e.code
 
-        except:
-            self.error = sys.exc_info()[1]
+        except BaseException as e:
+            self.error = e
             if fail_on_error:
                 raise
 
diff --git a/lib/spack/spack/test/llnl/util/lock.py b/lib/spack/spack/test/llnl/util/lock.py
index 4466d5999b..4d74d68d73 100644
--- a/lib/spack/spack/test/llnl/util/lock.py
+++ b/lib/spack/spack/test/llnl/util/lock.py
@@ -98,7 +98,7 @@
     comm = MPI.COMM_WORLD
     if comm.size > 1:
         mpi = True
-except:
+except ImportError:
     pass
 
 
@@ -234,7 +234,7 @@ def wait(self):
     if include:
         try:
             functions[subcomm.rank](subcomm_barrier())
-        except:
+        except BaseException:
             # aborting is the best we can do for MPI tests without
             # hanging, since we're using MPI barriers. This will fail
             # early and it loses the nice pytest output, but at least it
diff --git a/lib/spack/spack/util/module_cmd.py b/lib/spack/spack/util/module_cmd.py
index a726023d95..6a1db6d221 100644
--- a/lib/spack/spack/util/module_cmd.py
+++ b/lib/spack/spack/util/module_cmd.py
@@ -82,13 +82,13 @@ def get_module_cmd_from_bash(bashopts=''):
     try:
         find_exec = re.search(r'.*`(.*(:? bash | sh ).*)`.*', module_func)
         exec_line = find_exec.group(1)
-    except:
+    except BaseException:
         try:
             # This will fail with nested parentheses. TODO: expand regex.
             find_exec = re.search(r'.*\(([^()]*(:? bash | sh )[^()]*)\).*',
                                   module_func)
             exec_line = find_exec.group(1)
-        except:
+        except BaseException:
             raise ModuleError('get_module_cmd cannot '
                               'determine the module command from bash')
 
diff --git a/var/spack/repos/builtin/packages/charm/package.py b/var/spack/repos/builtin/packages/charm/package.py
index 944b46889f..7358b5588e 100644
--- a/var/spack/repos/builtin/packages/charm/package.py
+++ b/var/spack/repos/builtin/packages/charm/package.py
@@ -177,6 +177,6 @@ def install(self, spec, prefix):
                         shutil.copy2(filepath, tmppath)
                         os.remove(filepath)
                         os.rename(tmppath, filepath)
-                    except:
+                    except (IOError, OSError):
                         pass
         shutil.rmtree(join_path(prefix, "tmp"))
diff --git a/var/spack/repos/builtin/packages/hdf5-blosc/package.py b/var/spack/repos/builtin/packages/hdf5-blosc/package.py
index a12fb14d6d..9a472db102 100644
--- a/var/spack/repos/builtin/packages/hdf5-blosc/package.py
+++ b/var/spack/repos/builtin/packages/hdf5-blosc/package.py
@@ -184,7 +184,7 @@ def check_install(self, spec):
             try:
                 check = Executable("./check")
                 output = check(output=str)
-            except:
+            except ProcessError:
                 output = ""
             success = output == expected
             if not success:
diff --git a/var/spack/repos/builtin/packages/hdf5/package.py b/var/spack/repos/builtin/packages/hdf5/package.py
index d499898a9d..fea0006d09 100644
--- a/var/spack/repos/builtin/packages/hdf5/package.py
+++ b/var/spack/repos/builtin/packages/hdf5/package.py
@@ -270,7 +270,7 @@ def check_install(self):
             try:
                 check = Executable('./check')
                 output = check(output=str)
-            except:
+            except ProcessError:
                 output = ""
             success = output == expected
             if not success:
diff --git a/var/spack/repos/builtin/packages/plasma/package.py b/var/spack/repos/builtin/packages/plasma/package.py
index ffe0254651..0e8f7918f0 100644
--- a/var/spack/repos/builtin/packages/plasma/package.py
+++ b/var/spack/repos/builtin/packages/plasma/package.py
@@ -63,7 +63,7 @@ def edit(self, spec, prefix):
         for dep in ("blas", "lapack"):
             try:  # in case the dependency does not provide header flags
                 header_flags += " " + spec[dep].headers.cpp_flags
-            except:
+            except AttributeError:
                 pass
 
         make_inc.filter("CFLAGS +[+]=", "CFLAGS += " + header_flags + " ")
diff --git a/var/spack/repos/builtin/packages/python/package.py b/var/spack/repos/builtin/packages/python/package.py
index 15f2974328..b176169236 100644
--- a/var/spack/repos/builtin/packages/python/package.py
+++ b/var/spack/repos/builtin/packages/python/package.py
@@ -285,7 +285,7 @@ def _save_distutil_vars(self, prefix):
                     Python._DISTUTIL_CACHE_FILENAME)
                 with open(output_filename, 'w') as output_file:
                     sjson.dump(self._distutil_vars, output_file)
-            except:
+            except Exception:
                 tty.warn("Failed to save metadata for distutils. This might "
                          "cause the extensions that are installed with "
                          "distutils to call compilers directly avoiding "
@@ -308,7 +308,7 @@ def _load_distutil_vars(self):
                 if os.path.isfile(input_filename):
                     with open(input_filename) as input_file:
                         self._distutil_vars = sjson.load(input_file)
-            except:
+            except Exception:
                 pass
 
             if not self._distutil_vars: