Microsoft's planned upgrade of Hotmail users to its new Outlook.com service hit a snag today, with numerous reports of users being locked out of their accounts.
The problem seems to be affecting existing Hotmail users that have recently upgraded to Outlook, preventing them from accessing their emails when they try to sign in via its desktop and mobile sites.
Based on IT Pro's own investigation, non-Hotmail users that have signed up for Outlook.com accounts do not appear to be affected at this time in the UK.
Hotmail and Outlook.com users have used the social networking site Twitter to express their frustration at the service trouble, which is thought to have been going on for several hours.
One user, @WillGorgeousy, wrote: "@Microsoft Looks like the migration to Outlook isn't working. Hotmail down on the web. Keep us posted on any updates."
Meanwhile, Hotmail user @LouboutinJools claimed: "Absolutely nothing but grief with my Hotmail account since I [moved] to Outlook. Put it off for as long as you can."
IT Pro approached Microsoft for clarification about the number and general location of the affected users, but was still awaiting a response as this article went to press.
In the meantime, the Microsoft Support account on Twitter confirmed that "Hotmail/Outlook services are down" and that it is working to fix the issue.
The account also advises users to check its service status page, which at the time of publication reported no problems affecting Hotmail or Outlook.com.
News of the outage comes less than a week after Microsoft announced that it was stepping up its efforts to get Hotmail users to migrate to Outlook.com, as it prepares to retire its aging email brand.
This isn't the first time Hotmail users have run into problems with the move to Outlook, as many claimed to have been switched to Outlook.com without permission back in August 2012, and reported problems accessing emails.
Updated: Since IT Pro broke news of the Hotmail/Outlook outage yesterday, Microsoft have been in touch with a brief statement. In it, the company said the problem has now been fixed.
"Hotmail and Outlook.com experienced a short-term incident that caused a small percentage of customers not to be able to access their email. We worked quickly to resolve the issue, and service is now restored to normal; we sincerely apologise for any inconvenience this caused our customers," a company spokesperson wrote.
Whether or not yesterday's problems will affect Microsoft's reported momentum, when it comes to getting users to ditch Hotmail in favour of Outlook.com is anyone's guess, as the company recently claimed its new email client already has 60 million active users.
Get the ITPro. daily newsletter
Receive our latest news, industry updates, featured resources and more. Sign up today to receive our FREE report on AI cyber crime & security - newly updated for 2023.