Microsoft is not calling Tuesday's disruption to Hotmail and Outlook an outage, but the delays users are experiencing accessing email remain 12 hours after users first reported problems.
It's taking Microsoft "longer than hoped" to fix access problems with Hotmail and Outlook, with the service disruption which began Tuesday evening continuing through to Wednesday.
"We're having a problem accessing email. You might not be able to see all your messages," Microsoft notes on its status pages for Hotmail and Outlook for 12 March to 13 March.
Users took to Twitter to complain about being unable to open any emails on Tuesday, with the service returning a message selected could not be found and may have been moved or deleted.
Microsoft's Live Status page indicates the problems are ongoing, though it's not clear from the times made available which zone it's referring to. ZDNet has asked Microsoft for comment and is waiting on a response.
"We apologise for the lengthy interruption in service," it said in its latest update.
Outlook users were unable to access emails late last month during another service issue which locked them out of their accounts.
Though the cause of the problems remain unclear, Microsoft is in the middle of a major migration of Hotmail users to Outlook.com, which began days ahead of the 25 February outage. As reported by ZDNet, the migration will give Hotmail users Outlook.com's cleaner Metro-Style interface for their mail as well as calendars.
Microsoft also notes that it was performing maintenance on the Hotmail Calendar until 6pm PDT and warned of potential error messages and delays to syncing mail, contacts and calendar content to mail apps or phones.
Separate issues with SkyDrive were also resolved after a several hour disruption on Tuesday.