diff --git a/tests/test_offlinequeue.py b/tests/test_offlinequeue.py
index c4d21d2..dfbfcab 100644
--- a/tests/test_offlinequeue.py
+++ b/tests/test_offlinequeue.py
@@ -5,14 +5,20 @@ from wakatime.main import execute
 from wakatime.offlinequeue import Queue
 from wakatime.packages import requests
 
+import logging
 import os
 import sqlite3
 import sys
 import tempfile
 import time
+from testfixtures import log_capture
 from wakatime.compat import u
 from wakatime.packages.requests.models import Response
 from . import utils
+try:
+    from mock import call
+except ImportError:
+    from unittest.mock import call
 
 
 class OfflineQueueTestCase(utils.TestCase):
@@ -170,3 +176,35 @@ class OfflineQueueTestCase(utils.TestCase):
         db_file = queue.get_db_file()
         expected = os.path.join(os.path.expanduser('~'), '.wakatime.db')
         self.assertEquals(db_file, expected)
+
+    @log_capture()
+    def test_heartbeat_saved_when_requests_raises_exception(self, logs):
+        logging.disable(logging.NOTSET)
+
+        with tempfile.NamedTemporaryFile() as fh:
+            with utils.mock.patch('wakatime.offlinequeue.Queue.get_db_file') as mock_db_file:
+                mock_db_file.return_value = fh.name
+
+                self.patched['wakatime.packages.requests.adapters.HTTPAdapter.send'].side_effect = AttributeError("'Retry' object has no attribute 'history'")
+
+                now = u(int(time.time()))
+                entity = 'tests/samples/codefiles/twolinefile.txt'
+                config = 'tests/samples/configs/good_config.cfg'
+
+                args = ['--file', entity, '--config', config, '--time', now]
+                execute(args)
+
+                queue = Queue()
+                saved_heartbeat = queue.pop()
+                self.assertEquals(os.path.realpath(entity), saved_heartbeat['entity'])
+
+                self.assertEquals(sys.stdout.getvalue(), '')
+                self.assertEquals(sys.stderr.getvalue(), '')
+
+                output = [u(' ').join(x) for x in logs.actual()]
+                expected = u("AttributeError: \\'Retry\\' object has no attribute \\'history\\'")
+                self.assertIn(expected, output[0])
+
+                self.patched['wakatime.session_cache.SessionCache.get'].assert_called_once_with()
+                self.patched['wakatime.session_cache.SessionCache.delete'].assert_has_calls([call(), call()])
+                self.patched['wakatime.session_cache.SessionCache.save'].assert_not_called()
diff --git a/wakatime/main.py b/wakatime/main.py
index 2494fd3..c0969b3 100644
--- a/wakatime/main.py
+++ b/wakatime/main.py
@@ -187,7 +187,7 @@ def parseArguments():
     # update args from configs
     if not args.hostname:
         if configs.has_option('settings', 'hostname'):
-            args.hostname = configs.get('settings', 'hostname')    
+            args.hostname = configs.get('settings', 'hostname')
     if not args.key:
         default_key = None
         if configs.has_option('settings', 'api_key'):
@@ -388,6 +388,18 @@ def send_heartbeat(project=None, branch=None, hostname=None, stats={}, key=None,
                 log.warn(exception_data)
         else:
             log.error(exception_data)
+
+    except:  # delete cached session when requests raises unknown exception
+        exception_data = {
+            sys.exc_info()[0].__name__: u(sys.exc_info()[1]),
+            'traceback': traceback.format_exc(),
+        }
+        if offline:
+            queue = Queue()
+            queue.push(data, json.dumps(stats), plugin)
+            log.warn(exception_data)
+        session_cache.delete()
+
     else:
         code = response.status_code if response is not None else None
         content = response.text if response is not None else None