Scores of supermarket customers across South Yorkshire could be falling victim to a scam offering vouchers for Lidl - which then plagues your computer with viruses.
The fake offer is being shared on Facebook and promises shoppers a £45 voucher to celebrate the supermarket's anniversary.
But Lidl put a warning out on its own Facebook page warning customers that the deal is a scam.
The supermarket posted: "Dear Lidlers, a number of you have contacted us regarding a post to win a £45 voucher from Lidl via Facebook.
"Unfortunately this is a scam made to look like a voucher from us."
Clicking on the link directs you to a survey page, which you are then asked to share on your social media pages.
This then spams all of your friends with the same offer and the vicious cycle continues.
Lidl advises customers to always check its own competition page for all the latest news and deals.