Zotero crash when startup

Error description:
I just upgraded to 6.01, and didn't upgrade any plugins. When adding a paper from Chrome plugin, I found the new paper shows "0" in my database for multiple times. I tried to restart Zotero, but since then I can no longer open zotero. It keeps crashing when "waiting for zotero database..." and show the following error:

Error:
There was an error starting Zotero.
You can report this problem in the Zotero Forums.
Error: cleanDOI: argument must be a string cleanDOI@chrome://zotero/content/xpcom/utilities/utilities.js:407:15
_cacheKeyMappings@chrome://zotero/content/xpcom/retractions.js:773:21
From previous event:
ZoteroService@file:///C:/Program%20Files%20(x86)/Zotero/components/zotero-service.js:346:7
@chrome://zotero/content/include.js:4:14
This discussion has been closed.