diff --git a/onionshare/onionshare.py b/onionshare/onionshare.py
index 8b5d55d6..40a96c81 100644
--- a/onionshare/onionshare.py
+++ b/onionshare/onionshare.py
@@ -15,6 +15,10 @@ from stem.control import Controller
 from stem import SocketError
 
 from flask import Flask, Markup, Response, request, make_response, send_from_directory, render_template_string
+
+class NoTor(Exception):
+    pass
+
 app = Flask(__name__)
 
 strings = {}
@@ -109,7 +113,7 @@ def start_hidden_service(port):
         except SocketError:
             pass
     if not controller:
-        sys.exit(strings["cant_connect_ctrlport"].format(controlports))
+        raise NoTor(strings["cant_connect_ctrlport"].format(controlports))
     controller.authenticate()
 
     # set up hidden service
@@ -124,7 +128,15 @@ def main():
     global filename, filehash, filesize
     load_strings()
 
-    # validate filename
+    # try starting hidden service
+    port = choose_port()
+    print strings["connecting_ctrlport"].format(port)
+    try:
+        onion_host = start_hidden_service(port)
+    except NoTor as e:
+        sys.exit(e.args[0])
+
+    # select file to share
     if len(sys.argv) != 2:
         sys.exit('Usage: {0} [filename]'.format(sys.argv[0]));
     filename = sys.argv[1]
@@ -133,17 +145,10 @@ def main():
     else:
         filename = os.path.abspath(filename)
 
+    # startup
     print strings["calculating_sha1"]
     filehash, filesize = file_crunching(filename)
-    port = choose_port()
-
-    print strings["connecting_ctrlport"].format(port)
-    onion_host = start_hidden_service(port)
-
-    # punch a hole in the firewall
     tails_open_port(port)
-
-    # instructions
     print '\n' + strings["give_this_url"]
     print 'http://{0}/{1}'.format(onion_host, slug)
     print ''
diff --git a/onionshare_gui/onionshare_gui.py b/onionshare_gui/onionshare_gui.py
index 35e3b239..8adead85 100644
--- a/onionshare_gui/onionshare_gui.py
+++ b/onionshare_gui/onionshare_gui.py
@@ -49,9 +49,16 @@ def select_file(strings):
     return filename, basename
 
 def main():
-    # load strings
     strings = onionshare.load_strings()
 
+    # try starting hidden service
+    port = onionshare.choose_port()
+    try:
+        onion_host = onionshare.start_hidden_service(port)
+    except onionshare.NoTor as e:
+        alert(e.args[0], gtk.MESSAGE_ERROR)
+        return
+
     # select file to share
     filename, basename = select_file(strings)
     if not filename:
@@ -64,17 +71,11 @@ def main():
         quit_function=Global.set_quit)
     time.sleep(0.1)
 
+    # startup
     web_send("init('{0}', {1});".format(basename, json.dumps(strings)))
     web_send("update('{0}')".format(strings['calculating_sha1']))
     filehash, filesize = onionshare.file_crunching(filename)
-    port = onionshare.choose_port()
-
-    web_send("update('{0}')".format(strings['connecting_ctrlport'].format(port)))
-    onion_host = onionshare.start_hidden_service(port)
-
-    # punch a hole in the firewall
     onionshare.tails_open_port(port)
-
     url = 'http://{0}/{1}'.format(onion_host, onionshare.slug)
     web_send("update('{0}')".format('Secret URL is {0}'.format(url)))
     web_send("set_url('{0}')".format(url));