Microsoft has promised to look into complaints about its update to Windows Live Hotmail, and correct the situation as soon as possible.
Around 2,500 users have reported problems since the update went live at the end of October.
"We are actively investigating the issues noted by our customers and are working to take the appropriate steps to remedy the situation as rapidly as possible," said a Microsoft spokesman.
The company has already issued two statements about Hotmail this month, acknowledging the complaints and answering users' questions.
The Hotmail update included Contact Picker, which is designed to make it easier for users to look up contacts when writing an email, and predictive text when users start typing in an email address.
"No big changes, more like a repainted room than a remodelled house," the Hotmail team said in its update notice. "We've just made a few improvements to Hotmail based on feedback from customers like you."
However, Hotmail customers have been generally unimpressed with the changes, according to comments left on vnunet.com.
Users have been unable to access their folders and emails, and have had difficulty forwarding and replying to messages. Other users have said that the new Hotmail does not sit well with their screen size.
In response to a vnunet.com article published on 30 October, a reader called 'Yael' wrote: "Hotmail butchered the look and killed the user-friendliness of its website with this absolutely horrendous update. Auto-fill for addresses? Great, but not at such high cost; pretty much every other new feature and layout on there is absurd and more difficult to use."
Another vnunet.com reader, Barbara Chamberlain, wrote: "Hotmail no longer fits my screen, meaning I have to keep scrolling horizontally to read incoming and check outgoing emails."
Microsoft responded to the user feedback in a blog posting at the beginning of November, arguing that the changes were made in response to interviews with hundreds of users.
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