Microsoft is fixing a bug in Exchange Online that was incorrectly placing user mailboxes in quarantine.
Microsoft rolled out a patch for the online version of Exchange on Wednesday morning. It was much needed, as some users had been experiencing limited access to their mailboxes since the weekend. The update fixes a bug that erroneously placed mailboxes in ‘quarantine’.
Mailbox in quarantine
In IT terminology, quarantining means completely disconnecting a mailbox or other software from the internet and other systems. During cyberattacks, this can be a useful intervention to contain the spread of a virus. However, Exchange Online appeared to be isolating mailboxes without any cause.
For users, this meant that their mailboxes and calendars were suddenly unavailable, or that they could no longer send and receive emails. It is unknown how many users were affected by the bug. However, the first reports dated back to July 19. Affected users have therefore been without a functioning mailbox for several days.
End of support for Exchange 2016 and 2019
The software giant announced via the Microsoft 365 admin center that the problem has been resolved. Bugs in Microsoft’s mail server are a recurring issue. In February, Exchange Online’s phishing filters went into overdrive, causing legitimate emails to be labeled as malicious.
Users of older Exchange servers will soon no longer be able to hope for fixes for bugs and issues. Microsoft reminds that support for Exchange 2016 and Exchange 2019 expires in October. Extended support was extended by another six months in April, but then it will finally be over. The web version of Exchange has also no longer been available on older devices for some time.