Massive! Yahoo! Mail! outage! going! on! FOURTH! straight! day!

Yahoo! Mail is only now recovering from a massive outage that has delayed mail delivery and locked some users out of their accounts for the past several days.

"We can confirm that 97 per cent of affected users have access to their Mail accounts on web, POP and the Yahoo Mail iOS, Android and Windows 8 apps," the company wrote in a status update on Thursday.

That will be a welcome change for many of those who use Yahoo! Mail as their primary inbox, some of whom have been unable to access their accounts since 22.27 PT on Monday.

Those who prefer to access their accounts using the IMAP protocol rather than POP, however, are still having trouble. Yahoo! says that although POP access has been restored, it is "slowly ramping up IMAP access to ensure stability and maintain current users' access."

In addition to blocking some users from accessing their accounts, the prolonged outage has also affected mail delivery. As of Thursday, the Purple Palace reports that it has delivered the majority of its backlogged mail, but 20 per cent of messages sent to Yahoo! Mail inboxes between November 25 and December 9 are still queued for delivery.

Yahoo! has not given a clear explanation for the blackout, saying on Wednesday only that it was a "hardware problem" affecting servers in one of its mail data centers and that the issue has been more difficult to fix than it first expected.

Apparently it's not fixed yet, either. On Wednesday, Yahoo! said its engineers were working "through the night" to address the issues. As of midday Thursday, it said they are still working "tirelessly." Whoever supplies the coffee to Yahoo!'s Sunnyvale headquarters must be making a killing. ®