Tuesday was a frustrating day for many Outlook.com users as the service went into a spam meltdown, although it is not clear if this was the case for everyone. Nevertheless, the majority of Outlook.com users reported that their inboxes were overloaded with spam, leaving Microsoft scrambling for a fix.
It is not clear at this point what caused the spam filters to be down, but according to the current service status for Outlook.com, the issue has been solved.
Yesterday it was a different matter as many users thought it was a problem at their end, with most reporting dozens of spam emails. Other showed that they would be deleting a batch of dozens of spam when dozens more would appear in their inboxes. It is unclear where the spam content was coming from.
In the case of yours truly, most of the spams had a reference to my username within the title or subject of the spam mail. This meant it was an easy case of searching a single term and deleting the spam in one chunk, but others report that deleting the emails took a long time. Microsoft acknowledged the issue and said it was solving it:
“We're implementing two fixes. One will provide short-term relief preventing spam reaching your inbox. The second will be a longer term fix which should stop spam reaching our infrastructure.”
As mentioned, the problem has now been fixed, but the Outlook team did not give any details on the cause of the issue or whether it could happen again.