Bug when downloading metadata for many books

When I try to download metadata for 37 books I get the following stack trace:
calibre, version 0.8.59
ERROR: Failed to download metadata: <b>Failed</b>: Download metadata for 37 books

Starting job: Download metadata for 37 books
Job: "Download metadata for 37 books" failed with error:
Traceback (most recent call last):
File "site-packages\calibre\gui2\threaded_jobs.py", line 83, in start_work
File "site-packages\calibre\gui2\metadata\bulk_download.py", line 236, in download
File "site-packages\calibre\utils\ipc\simple_worker.py", line 158, in fork_job
File "site-packages\calibre\utils\ipc\simple_worker.py", line 75, in communicate
WorkerError: Failed to connect to worker process

Called with args: ([1268, 1267, 1266, 1265, 1264, 1263, 1262, 1261, 1260, 1259, 1258, 1257, 1256, 1255, 1254, 1253, 1252, 1251, 1250, 1249, 1248, 1247, 1246, 1245, 1244, 1243, 1242, 1241, 1240, 1239, 1238, 1237, 1236, 1235, 1234, 1233, 1232], u'C:\\Users\\Andrew\\AppData\\Local\\Temp\\calibre _0.8.59_tmp_zi8ekt\\n9q8hs_metadata_bulk.log', <calibre.library.database2.LibraryDatabase2 object at 0x04BC8A10>, True, False, None) {u'notifications': <Queue.Queue instance at 0x15C80120>, u'abort': <threading._Event object at 0x158C82D0>, u'log': <calibre.utils.logging.GUILog object at 0x15803E70>}

Any simple advice to download a pile of metadata at one time, or do I need to wait for a fix?