diff --git a/scrapy/crawler.py b/scrapy/crawler.py
index ded09c1c7..6866be809 100644
--- a/scrapy/crawler.py
+++ b/scrapy/crawler.py
@@ -156,7 +156,8 @@ class CrawlerProcess(CrawlerRunner):
         reactor.run(installSignalHandlers=False)  # blocking call
 
     def _stop_logging(self):
-        self.log_observer.stop()
+        if self.log_observer:
+            self.log_observer.stop()
 
     def _stop_reactor(self, _=None):
         try:
diff --git a/tox.ini b/tox.ini
index 624f550e1..8aeb1492e 100644
--- a/tox.ini
+++ b/tox.ini
@@ -25,7 +25,6 @@ deps =
     lxml==2.3.2
     Twisted==11.1.0
     boto==2.2.2
-    Pillow<2.0
     django==1.3.1
     cssselect==0.9.1
     zope.interface==3.6.1