Suddenly Not Able to Login due to Cookie error

Hi,
This issue was reported 5 months ago in the thread “Cookie Error when Logging In”.

I can’t login to my dashboard and get the error message:

ERROR: Cookies are blocked or not supported by your browser. You must enable cookies to use WordPress.

Have tried the usual fixes like, re-enter login in error login, deactivate plugins, and followed Google’s instructions in the anchor text of the error message to no avail.

On the forum thread, one member said:

“It is apparently a login update with WordPress. An “improved” control mechanism during the login process to check if a browser can store cookies. This cookie, however, is only set in the wp-login.php file and in many login scenarios, the cookie is set too late to be of any real use.”

He suggested – Comment out lines 744-746 in wp-login.php. This will bypass the check entirely and logs you in.

It should look like this:

//	if ( isset($_POST['testcookie']) && empty($_COOKIE[TEST_COOKIE]) )
//		$user = new WP_Error('test_cookie', __("<strong>ERROR</strong>: Cookies are blocked or not supported by your browser. You must <a href='https://www.google.com/cookies.html'>enable cookies</a> to use WordPress."));
//	else
		$user = wp_signon('', $secure_cookie);

THE RELEVANT SECTION IN MY WP-LOGIN.PHP FILE LOOKS LIKE THIS:

//Set a cookie now to see if they are supported by the browser.

setcookie(TEST_COOKIE, 'WP Cookie check', 0, COOKIEPATH, COOKIE_DOMAIN);
if ( SITECOOKIEPATH != COOKIEPATH )
	setcookie(TEST_COOKIE, 'WP Cookie check', 0, SITECOOKIEPATH, COOKIE_DOMAIN);/**
 * Fires when the login form is initialized. * * @since 3.2.0 */
do_action( 'login_init' );/** * Fires before a specified login form action. *
 * The dynamic portion of the hook name, $action, refers to the action
 * that brought the visitor to the login form. Actions include 'postpass',
 * 'logout', 'lostpassword', etc. * * @since 2.8.0 */
do_action( 'login_form_' . $action );

* The dynamic portion of the hook name, $action, refers to the action
 * that brought the visitor to the login form. Actions include 'postpass',
 * 'logout', 'lostpassword', etc. * * @since 2.8.0 */
do_action( 'login_form_' . $action );
$http_post = ('POST' == $_SERVER['REQUEST_METHOD']);
$interim_login = isset($_REQUEST['interim-login']);switch ($action) {
case 'postpass' :	require_once ABSPATH . 'wp-includes/class-phpass.php';
	$hasher = new PasswordHash( 8, true );	/**
	 * Filter the life span of the post password cookie.	 *
	 * By default, the cookie expires 10 days from creation. To turn this
	 * into a session cookie, return 0.	 *	 * @since 3.7.0	 *
	 * @param int $expires The expiry time, as passed to setcookie().	 */
	$expire = apply_filters( 'post_password_expires', time() + 10 * DAY_IN_SECONDS );
	setcookie( 'wp-postpass_' . COOKIEHASH, $hasher->HashPassword( wp_unslash( $_POST['post_password'] ) ), $expire, COOKIEPATH );

Not sure where and how to apply that suggested fix into this code.
Please help!! What has caused this to happen so I can avoid it?

Thanks for your time WP developers.

PS – Just noticed from drop-down list here that there is a new upgrade to version 3.8.2. Does this have anything to do with it? I cant upgrade without logging in.