diff --git a/src/calibre/gui2/viewer/main.py b/src/calibre/gui2/viewer/main.py
index e113ef0611..09019af18b 100644
--- a/src/calibre/gui2/viewer/main.py
+++ b/src/calibre/gui2/viewer/main.py
@@ -716,6 +716,9 @@ View an ebook.
 
 
 def main(args=sys.argv):
+    # Ensure viewer can continue to function if GUI is closed
+    os.environ.pop('CALIBRE_WORKER_TEMP_DIR', None)
+
     parser = option_parser()
     opts, args = parser.parse_args(args)
     pid = os.fork() if False and (islinux or isfreebsd) else -1
diff --git a/src/calibre/utils/ipc/worker.py b/src/calibre/utils/ipc/worker.py
index e3584380a1..d8ffad7c53 100644
--- a/src/calibre/utils/ipc/worker.py
+++ b/src/calibre/utils/ipc/worker.py
@@ -105,7 +105,7 @@ def main():
             notifier.start()
 
         result = func(*args, **kwargs)
-        if result is not None:
+        if result is not None and os.path.exists(os.path.dirname(resultf)):
             cPickle.dump(result, open(resultf, 'wb'), -1)
 
         notifier.queue.put(None)