<p>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.</p><p>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.</p><p>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.</p><p>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.</p><p><a href="http://www.itpro.co.uk/email-clients/19294/hotmail-problems-blight-outlook-migration-users-report-service-trouble">Keep reading...</a></p><p>Read also:</p><p><a href="http://www.zdnet.com/outlook-com-outage-leaves-users-locked-out-of-accounts-7000011792/">Outlook.com outage leaves users locked out of accounts</a> (ZDNet)</p><p>Explore: <a href="http://news.google.com/news/more?ncl=dHNP4cshbV9l7oMSN_duybWgLoziM&ned=us">2 additional articles.</a></p>