I’m now having exactly the same issues; a site that was working perfectly prior to the update now issues the “Error: Cookies are disabled or…” message whenever *anyone* tries to log on. (Site is https://www.greenlandgown.org)
Nothing on the site was changed other than the WP 3.7.1 update; This issue is cross-browser.
I’ve disabled all plugins and switched to a stock twenty twelve theme to no avail. I’ve clear cache and cookies on Chrome, Firefox, IE and Safari, all to no avail.
Apparently as part of the new update login.php is now issuing a test cookie that is not being properly read on the first pass. If you enter the username and password on the error page, the system will allow you to log on. Alas, most users won’t try a second time.
So, basically, this nifty new update has tanked my – and a great many other users – ability to have people log on to their WordPress sites.
Any ideas how to fix this?