I've been having the same issue for about 2 weeks. Perhaps an update messed it up, as it was fine before that.
It gets up to "Scanning posts for URL's in Google's Safe Browsing List" and then gets stuck there (for days). Always the same step, which it seems others are getting stuck on too despite having plenty of memory.
Any help would be appreciated.
I considered uninstalling and reinstalling, but did not want to lose my settings and blocked IPs.