In Lexington, Kentucky, one Twitter user tweeted a photo and wrote, "What Kroger's in #Lexington looks like at 1 p.m. on Christmas Eve when the registers go down and only cash accepted. Guy who seemed to be in charge said it's systemwide. But the computers started functioning correctly intermittently."
While the systems were down, customers piled into nearby banks to get cash, causing long lines at teller lines and ATMs.
Kroger has more than 4,000 stores nationwide, mostly in the South and Midwest.
Despite the frustration, there were still acts of kindness among shoppers.
"The cutest old man just (paid) for our groceries at Kroger because the credit card machines were down," one Twitter user tweeted.