Plus, why you’ll hopefully hear that dreaded sentence less frequently in the future.

Number yourself among the luckiest if you’ve never coasted through a McDonald’s drive-thru, eyes on the prize—an Oreo McFlurry—just to have your dreams crushed by the cruel words of an employee: “Sorry, the ice cream machine is down.”

If you’ve heard those devastating words, you’re far from alone. Indeed, complaints about the MIA soft-serve machine number so high they were McDonald’s greatest customer complaint a few years ago.

This soft-serve scandal has stirred up social media rants, taunting marquee signs from competing fast-food restaurants, and a torrent of Twitter tirades. It’s also led to a series of conspiracies, all of which may, in some way, explain why the machine never seems to work just when you’re craving a spoonful of ultra-creamy vanilla ice cream.

The ice cream-dispensing machine is subject to lengthy cleaning measures, McDonald’s told the Wall Street Journal. The four-hour cleaning process, designed to kill bacteria and prevent foodborne illness, requires partial disassembly and extensive scrubbing of fixed machine parts.

Indeed, the manufacturer's operating manual details a 12-step process that involves a series of cleaning, sanitizing, scrubbing, and then waiting for the pieces to dry before the machine can be operational again. Once the process begins, it can’t be stopped mid-steam.

“The product is hot and under extreme pressure,” the manual says of the process’s heat cycle.

McDonald’s told WSJ they encourage stores to perform the machine maintenance in down hours, but that’s just when many cravings for the creamy, cold sweet treat hit. If you wheel into the drive-thru for a late-night snack, you may get the bad news more frequently.

Plus, many McDonald’s stores are open 24 hours now, leaving essentially no time when the machine definitely won’t be in demand.

“We regularly service our soft-serve equipment during off-peak hours,” a company spokeswoman told WSJ. “Customers who come in during that time may encounter a longer wait time or soft-serve dessert unavailability.”

On Twitter and Reddit, the theories for the absentee ice cream machine have a bit more blame to pass to the people who man the machines. The conjecture on these platforms is that McDonald’s employees start the cleaning process early, creating a wider window of time without the ice cream machine.

When they start disassembling the machine and washing the parts, there’s little incentive to reassemble the machine when a lone request for a McFlurry comes through. It’s perhaps easier to say the machine is down than take the time to reassemble.

Former and current McDonald’s employees also report that the McFlurry machines happen to be quite temperamental, too. Indeed, the WSJ also reported that a 2000 survey found that one-quarter of ice cream units in McDonald’s stores were not working properly. It may be easier to ignore the machine altogether.

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In a Reddit Ask Me Anything, a McDonald’s employee wrote, “The modern ice cream machines have a mandatory heat treatment cycle that takes a minimum of 3 hours to complete, and much longer If the machines [sic] is not prepared for it. In addition, they must be disassembled for cleaning every 14 days, and if that cleaning is not completed the machines locks out.

“In addition, improper maintance [sic] or parts failure can easily cause the machine to be unable to maintain minimum performance, causing another lock out,” the Reddit user wrote.

Good news, however: It seems the screams about ice cream machines have been heard, and McDonald’s decided to respond. In spring 2017, the fast-food giant announced they would be installing easier-to-maintain ice cream machines in the U.S. and Europe beginning in the fourth quarter of that year.

That means you could be among the lucky populace with a new machine right now, and if you’re not yet, stay tuned. McDonald’s is looking for ways to boost their annual dessert profits (among their cooling profits), and fully functional Flurry machines in their more than 36,000 stores just might be step number one.