What if a slot machine malfunctions?

What if a slot machine malfunctions? The short answer

A slot machine malfunction is any fault that stops the game working as designed: a frozen screen, reels that stop in the wrong place, a coin taken but not counted, a prize that won't pay, or a display that shows something the game never decided. What you're owed depends on what the machine actually recorded.

Your stake isn't lost to a fault: games that broke before producing a result should return it, and genuine wins recorded by the system should be paid. Equally, a casino or venue doesn't have to pay a prize that exists only because of the error. This answer is part of our slot machine questions series.

Common kinds of slot machine malfunction

What "malfunction voids all pays and plays" means

Many casino terms include wording along these lines: if a game malfunctions, affected bets and payouts are void. Read properly, it is a two-way rule. Voiding a play means your stake is returned, as though the game never happened; it isn't a licence to keep your money and cancel your win.

Terms must also be fair and clearly set out. The Commission fined Taichi Tech £170,000 in July 2025 partly over a term letting it forfeit winnings at its discretion (opens in a new tab). A malfunction clause should cover a real, identifiable fault, and an ADR provider can look at whether it was applied fairly.

Why the screen isn't always the result

On modern slots, the outcome is decided by the random number generator when the spin starts. The reels are an animation of that result. Online, the result is calculated and logged on the provider's server, as explained in how online slots work; a land-based machine records it in its own software and meters.

That separation is why a fault in the graphics, such as reel strips appearing to land on a jackpot line, doesn't create a jackpot. The operator checks the log. It cuts both ways: if the display froze but the log shows a win, you're paid the win.

Displayed wins above the machine's maximum prize

Land-based machines have legal prize caps by category, set out in our guide to UK slot machine categories. A pub fruit machine is Category C: £1 maximum stake, £100 maximum prize. If a fault shows £5,000 on that machine, the venue can't lawfully pay it, because no Category C game can offer it. The same logic applies at £500 for Category B3 and B2, and £10,000 (or £20,000 linked) for B1 in casinos.

Online slots have no statutory prize cap, but each game has a max win cap in its rules; a result above it points to an error. See the maximum prize on a pub fruit machine.

What to do if a slot machine malfunctions: step by step

1. Stop playing. Don't press buttons, refresh repeatedly or feed in more money.
2. Note the time, machine number or game name, stake and what the screen shows.
3. Take a photo or screenshot if you can do so without breaking venue rules.
4. In a venue, call a member of staff and stay by the machine until they arrive.
5. Online, contact support and ask them to check the game round in your history.
6. Ask for the outcome and the reason in writing.
7. If you disagree, make a formal complaint; after 8 weeks you can go to ADR.

Malfunctions on pub, arcade and casino machines

Staff can open a machine, clear a jammed coin or note, and read its meters, which keep a running count of money in, money out and games played. Most refunds for uncredited money are settled on the spot. Category B1, B2, B3 and B3A machines must be tested by an independent test house approved by the Commission before they're used; our guide to how slot machines are tested explains the process.

Since 29 July 2026, licensees must take specified non-compliant machines out of use once the Commission tells them to in writing. New gaming machine technical standards follow on 30 March and 30 June 2027.

Malfunctions on online slots

The Commission's remote technical standards (opens in a new tab) include a section on interrupted gambling (RTS 10). It requires operators' policies on service interruptions to be fair and not systematically disadvantage customers, systems that can recover from failures and void gambles where appropriate, and published information on how interruptions are handled.

The guidance for gaming says a result already generated stands; a single-stage game that fails before an outcome should return the stake; a multi-stage game, such as a bonus round, should be restored to its last known state so you can finish it; and progressive jackpot values should be restored to their pre-failure level. A dropped connection is covered separately in what happens if my connection drops mid spin.

How UK testing reduces slot malfunctions

Online slot software and machine software must be checked by a Commission-approved test house. In March 2026 there were 14 on the list, including eCOGRA, GLI and BMM, with only some approved for land-based machines. Testing covers the RNG certification, paytable maths and the rules on speed and display.

Faults in compliance get caught too. In June 2026 Stakelogic BV agreed to pay £122,835 after some of its slots ran faster than the 2.5-second minimum spin time. That is a reminder that "malfunction" can mean breaking the rules, not just breaking down.

If you disagree with the decision on a malfunction

Ask for a written explanation and the game round data. If you're still unhappy, use the operator's complaint process. It has 8 weeks to resolve it; after that, or after a final answer you don't accept, it must refer you to its alternative dispute resolution provider, which is free for you. Our pages on slot complaints and ADR and whether a casino can refuse to pay a slot win explain what an adjudicator weighs.

Slot machine malfunction myths

See can you trick a slot machine and can slot machines be hacked for more.

Where to play: licensed casinos and faults

Playing with a casino licensed by the Gambling Commission means its games are tested, its interruption policy must be published, and you have a free ADR route if a malfunction dispute goes wrong. Our partners below are all licensed in Great Britain. Game availability changes, so search each casino's lobby for a title.

• Coral: 18+ new players; deposit (certain methods excluded) and bet £10 on slots for 100 free spins at 10p on selected games, to be accepted within 48 hours and used within 7 days. No wagering on winnings; offer runs until 1 February 2027.
• Ladbrokes: 18+ new customers; deposit and spend £10 on slots for 50 free spins a day over 10 days (up to 500), 10p each, claimed before 23:59 each day and valid 7 days. No wagering; PayPal, Paysafe, Neteller, Skrill and prepaid deposits excluded.
• PlayOJO: 18+ new UK customers outside Northern Ireland; first deposit of at least £10 brings 80 free spins at 10p on Big Bass Bonanza, with winnings paid in cash and no wagering.

Coral and Ladbrokes share an operator, so check whether you can hold new accounts at both. Terms apply.

18+. Gambling should be entertainment that costs money, not a way to make it. Decide a budget before you play: plan a slot budget. Free, confidential help: National Gambling Helpline 0808 8020 133.