Facebook's latest revamp has upset some members by recommending they get in touch with friends who have died.
The social networking site, which is used by 300 million people worldwide, made the controversial changes over the weekend. One of the most prominent additions is an automatically generated box suggesting the user "reconnect" with a specific person they have not contacted for a while.
But within hours, dozens of users reported feeling distressed when the new feature told them to get in touch with someone deceased. More than 900,000 have reacted against the changes by joining a group calling for the site to go "back to normal."
"Facebook just suggested that I reconnect with someone who passed away two years ago. That's messed up," one person wrote on Twitter.
Another user, Emma, 27, was confronted by the image of a deceased friend when she logged into the site over the weekend. "Like many of his friends, I haven't deleted his profile as that would feel weird. I'm sure thousands of Facebook users are in the same position," she told Sky News Online.
"When someone dies there doesn't seem to be much you can do about their profile. It would be nice to keep it as a memorial but there is no way of acknowledging what has happened to that person.
"There should be a way of recognizing this on their profile or Facebook should remove the feature altogether to avoid causing offence."
The glitch reveals the "insensitivity of the algorithm," according to Mashable blogger Pete Cashmore. He also found examples of the site suggesting ex husbands and wives.
"Facebook is investigating the situation," a spokeswoman told Sky News Online.