Swollen MacBook battery? What to do straight away
7 November 2026 · Mac guides
Your MacBook's trackpad has started to feel stiff, or it has risen slightly above the case. The lid won't quite shut, the laptop rocks on the desk, or the base has a bulge that wasn't there before. These are the classic signs of a swollen battery, and it is the one Mac fault where we would say stop using it today rather than when you get round to it.
Why batteries swell
MacBooks use lithium-ion batteries. As they age, or if they are damaged, chemical changes inside the cells can produce gas. The cells are sealed in soft pouches, so the gas has nowhere to go and the pouch puffs up. Age and heat make this more likely. So does a knock or liquid getting into the laptop, and a MacBook left plugged in somewhere hot for years is a common case.
In a MacBook the battery sits directly under the trackpad and palm rests, with very little spare room. That is why the trackpad is so often the first thing to show it.
The signs to look for
- The trackpad is hard to click, clicks by itself, or stands proud of the case.
- The lid no longer closes flat, or the screen touches the keyboard in places.
- The bottom case is bowed, or a corner has lifted away.
- The MacBook no longer sits flat on a table.
- Keys feel uneven around the middle of the keyboard.
- Battery life has dropped suddenly, or the Mac shuts down at a healthy-looking percentage.
You might also see Service Recommended under Battery in System Settings. Don't take a clean bill of health there as proof that all is well, though. A battery can swell without the software warning you, so believe what you can see.
What to do now
- Unplug the charger and don't charge it again.
- Copy your most important files off, if you can do so quickly. If the Mac is cool and working normally, a short backup to an external drive or iCloud is reasonable. Then shut it down properly.
- Put it somewhere safe. Leave it on a hard, non-flammable surface away from anything that could burn, and not on a bed, a sofa or in a bag.
- Book it in promptly. A swollen battery doesn't recover, and it can get worse.
If it is hot, hissing or giving off a sweet or chemical smell, don't try to back it up. Keep clear of it, move away from any smoke, and call the fire service if it catches fire.
What not to do
- Don't press it flat. Pushing the trackpad back down or closing the lid firmly puts pressure on damaged cells.
- Don't puncture it. Old internet guides suggest releasing the gas. This is dangerous, because a damaged cell can catch fire.
- Don't try to remove it yourself. Batteries in recent MacBooks are held in with strong adhesive, and levering them out risks piercing a cell.
- Don't post it without asking first. Carriers restrict damaged lithium batteries, so speak to us before you send it anywhere or carry it on a plane.
Can your MacBook be saved?
Usually, yes. Swelling is often caught while the rest of the laptop is fine, and a new battery puts things right. It depends how far it has gone, because the pressure can also cause other damage:
- Trackpad: it may settle back once the pressure is gone, or it may have been bent and need replacing.
- Top case and keyboard: these can be distorted, and on many models the keyboard is part of the top case. See Mac keyboard replacement.
- Screen: if the trackpad or keyboard has been pushed against the display when closed, there may be marks or cracks. See Mac screen repair.
- Logic board: usually unaffected, but we check it before recommending anything.
One thing to watch: replacing the trackpad alone doesn't solve anything. If someone offers that without checking the battery, ask why.
On an older MacBook where several parts have been damaged, the sums may not work out. If that is the case we'll say so, and there are still options if a repair isn't worth it.
Are your files safe?
A swollen battery doesn't normally harm the data on the Mac. The storage is separate from the battery, and your files should still be there once the Mac has been made safe. The risk comes if you carry on using a Mac with an unstable battery, or it fails during a repair attempt at home.
On recent MacBooks the storage is built into the logic board, so the Mac needs to be working to get the files off. If you have no backup, tell us when you book in. If the Mac won't start, we offer a free assessment for Mac data recovery.
Keeping the next battery healthy
You can't prevent ageing, but you can slow it down. Keep your MacBook out of hot cars and direct sun, make sure it can shed heat when it is working hard, and leave Optimised Battery Charging switched on. If you store a MacBook for months at a time, leave it about half charged rather than flat or full, and check it every so often. Look at any spare MacBook in a drawer too, because a battery can swell while the laptop sits unused.
Get a quote
Call 020 7394 2525 and tell us what you can see, so we can advise on the safest way to get it to us. You'll find us at 80 Willow Walk, London SE1 5SY, 9am to 6pm, Monday to Saturday.