diff --git a/calibre-plugin/fff_plugin.py b/calibre-plugin/fff_plugin.py
index 96dd1153..43c2fd54 100644
--- a/calibre-plugin/fff_plugin.py
+++ b/calibre-plugin/fff_plugin.py
@@ -1700,9 +1700,8 @@ class FanFicFarePlugin(InterfaceAction):
         options['plugin_path'] = self.interface_action_base_plugin.plugin_path
 
         func = 'arbitrary_n'
-        cpus = self.gui.job_manager.server.pool_size
         args = ['calibre_plugins.fanficfare_plugin.jobs', 'do_download_worker',
-                (book_list, options, cpus, merge)]
+                (book_list, options, merge)]
         desc = _('Download %s FanFiction Book(s)') % sum(1 for x in book_list if x['good'])
         job = self.gui.job_manager.run_job(
                 self.Dispatcher(partial(self.download_list_completed,options=options,merge=merge)),
diff --git a/calibre-plugin/jobs.py b/calibre-plugin/jobs.py
index f5916e69..2a814aa4 100644
--- a/calibre-plugin/jobs.py
+++ b/calibre-plugin/jobs.py
@@ -39,16 +39,19 @@ except NameError:
 
 def do_download_worker(book_list,
                        options,
-                       cpus,
                        merge=False,
                        notification=lambda x,y:x):
     '''
-    Coordinator job, to launch child jobs to extract ISBN for a set of books
+    Coordinator job, to launch child jobs to do downloads.
     This is run as a worker job in the background to keep the UI more
-    responsive and get around the memory leak issues as it will launch
+    responsive and get around any memory leak issues as it will launch
     a child job for each book as a worker process
     '''
-    server = Server(pool_size=cpus)
+    ## pool_size reduced to 1 to prevent parallel downloads on the
+    ## same site.  Also prevents parallel downloads on different
+    ## sites.  Might do something different to allow that again
+    ## someday.
+    server = Server(pool_size=1)
 
     logger.info(options['version'])
     total = 0