Instagram has apologised after a test feature was accidentally rolled out to millions of people using its app.
The change meant moving through a feed had to be done by swiping horizontally rather than vertically.
Almost as soon as the change was made, users took to Twitter to complain and demand the return of the familiar up-and-down scrolling method.
The unwelcome update - which was likened to Tinder - was live for about an hour before it was rolled back.
In a tweet, Instagram's head of product Adam Mosseri said: "Sorry about that, this was supposed to be a very small test but we went broader than we anticipated."
The change trended under the #instagramupdate hashtag on Twitter, accompanied by mostly negative comments.
Many asked who had thought changing the scrolling direction would be a good idea. Several called on co-founders Kevin Systrom and Mike Krieger - who quit earlier this year - to return.
Some wondered if it was a way to stop people just scrolling endlessly through updates by making them tap and examine posts before moving on.
Instagram user Elise Michelle called it: "By far the worst update in Instagram history."
Soon after the backlash, Mr Mosseri tweeted that the change had been "rolled back".
He added: "If you're still seeing it you can simply restart your app and you should be good to go."
Has Instagram lost its mind? I am not tinder swiping through everyone’s posts 🤔😒 #instagramupdate— rush (@therushahead) December 27, 2018
Only in 2018 could a company as large as Instagram release a new update and then receive such a backlash over it that they change it back 20 minutes later. Beautiful. #instagramupdate— Michael (@michaelbrown_10) December 27, 2018
You should see the comments on my past Instagram post... pic.twitter.com/gTMW3qUbjN— Adam Mosseri (@mosseri) December 27, 2018