Our Sharepoint servers were shut down safely as part of a backup, and when brought back online we noticed multiple errors in the crawl log, and no successes. The error was "The account password was not specified. Specify the password." As specified here: http://blog.sharepointsite.co.uk/2011/07/sp2010-enterprise-search-crawl-log.html, we re-entered the password for the Default Content Access Account (SP_Crawl), which was accepted.
After this password was entered, the error in the crawl log changed to "Item was not crawled because of a password change. Update password and retry crawling.", and the same number of errors persisted. We tried re-entering the correct password but it has made no difference. The crawl is now completely inoperative and not indexing any new content.
There seems to be very little information online about these errors, and we are at a loss as to why this would have happened after a simple server restart. (The servers are restarted fairly regularly for patch installations and upgrades.)
The password for the account is definitely correct, as we are able to log onto the servers using this domain account.
Any thoughts welcome, thanks.