# 500: Internal server error. Mac, OS 10.9

I tried to install sage on an other Mac with OS10.9.5. I compield it myself, the tests run without error. But when I try to start the notebook, the browser window opens with sage, but reports:

500: Internal server error.

The complete output of the terminal see below. The only particular thing with this Mac is that it has no (and will not have) connection to the internet.

Any Ideas waht could be the problem?

```
notebook()
The notebook files are stored in: sage_notebook.sagenb
┌────────────────────────────────────────────────┐
│ │
│ Open your web browser to http://localhost:8080 │
│ │
└────────────────────────────────────────────────┘
Executing twistd --pidfile="sage_notebook.sagenb/sagenb.pid" -ny "sage_notebook.sagenb/twistedconf.tac"
/Volumes/DatenYM/Progr/Sage/sage-6.6/local/lib/python2.7/site-packages/Crypto/Util/number.py:57: PowmInsecureWarning: Not using mpz_powm_sec. You should rebuild using libgmp >= 5 to avoid timing attack vulnerability.
_warn("Not using mpz_powm_sec. You should rebuild using libgmp >= 5 to avoid timing attack vulnerability.", PowmInsecureWarning)
2015-05-06 13:39:05+0200 [-] Log opened.
2015-05-06 13:39:05+0200 [-] twistd 14.0.2 (/Volumes/DatenYM/Progr/Sage/sage-6.6/local/bin/python 2.7.8) starting up.
2015-05-06 13:39:05+0200 [-] reactor class: twisted.internet.selectreactor.SelectReactor.
2015-05-06 13:39:05+0200 [-] QuietSite starting on 8080
2015-05-06 13:39:05+0200 [-] Starting factory <__builtin__.QuietSite instance at 0x11522d5f0>
[Errno 66] Directory not empty
Traceback (most recent call last):
File "/Volumes/DatenYM/Progr/Sage/sage-6.6/local/lib/python2.7/site-packages/Flask-0.10.1-py2.7.egg/flask/app.py", line 1475, in full_dispatch_request
rv = self.dispatch_request()
File "/Volumes/DatenYM/Progr/Sage/sage-6.6/local/lib/python2.7/site-packages/Flask-0.10.1-py2.7.egg/flask/app.py", line 1461, in dispatch_request
return self.view_functions[rule.endpoint](**req.view_args)
File "/Volumes/DatenYM/Progr/Sage/sage-6.6/local/lib/python2.7/site-packages/sagenb-0.11.4-py2.7.egg/sagenb/flask_version/decorators.py", line 22, in wrapper
return f(*args, **kwds)
File "/Volumes/DatenYM/Progr/Sage/sage-6.6/local/lib/python2.7/site-packages/sagenb-0.11.4-py2.7.egg/sagenb/flask_version/worksheet_listing.py", line 67, in home
return render_worksheet_list(request.args, pub=False, username=username)
File "/Volumes/DatenYM/Progr/Sage/sage-6.6/local/lib/python2.7/site-packages/sagenb-0.11.4-py2.7.egg/sagenb/flask_version/worksheet_listing.py", line 43, in render_worksheet_list
search=search, reverse=reverse)
File "/Volumes/DatenYM/Progr/Sage/sage-6.6/local/lib/python2.7/site-packages/sagenb-0.11.4-py2.7.egg/sagenb/notebook/notebook.py", line 1295, in worksheet_list_for_user
X = self.get_worksheets_with_viewer(user)
File "/Volumes/DatenYM/Progr/Sage/sage-6.6/local/lib/python2.7/site-packages/sagenb-0.11.4-py2.7.egg/sagenb/notebook/notebook.py", line 1477, in get_worksheets_with_viewer
if self._user_manager.user_is_admin(username): return self.get_all_worksheets()
File "/Volumes/DatenYM/Progr/Sage/sage-6.6/local/lib/python2.7/site-packages/sagenb-0.11.4-py2.7.egg/sagenb/notebook/notebook.py", line 1472, in get_all_worksheets
for w in self.users_worksheets(username):
File "/Volumes/DatenYM/Progr/Sage/sage-6.6/local/lib/python2.7/site-packages/sagenb-0.11.4-py2.7.egg/sagenb/notebook/notebook.py", line 380, in users_worksheets
worksheets = self.__storage.worksheets(username)
File "/Volumes/DatenYM ...
```

This is the same question as http://ask.sagemath.org/question/9845... I think.

Although usually this error only shows up when one uses Sage across platforms. Can you diagnose this by doing

`sage -sh; echo $DOT_SAGENB`

in your terminal? If you truly have not used Sage on this computer, you could just remove the`.sage/sage_notebook.sagenb`

folder with no ill effects, I think.I did a clean install on the other Mac, and did not copy anything from the first Mac. But I tried sage some years ago.

Deleting .sage/sage_notebook.sagenb has solved the problem.

The output of the shell is