What Was Happening
A customer from Putney SW15 brought in their MacBook Pro 13-inch 2017 (A1708) after the trackpad had stopped responding reliably. Clicks were registering inconsistently, and the trackpad surface had developed a slight resistance that wasn’t there before. They had also noticed the bottom of the MacBook seemed to be sitting unevenly on their desk — one corner was slightly raised.
The machine was otherwise functional: it powered on, the keyboard worked, and the screen was fine. The customer suspected a software problem and had already tried resetting the SMC and NVRAM without improvement.
Our Diagnosis
Physical inspection immediately confirmed this was a hardware issue rather than a software one. The base panel of the MacBook was visibly bowing — a classic sign of a swollen lithium polymer battery. The battery on the A1708 sits directly beneath the trackpad assembly, and as it expands it presses upward against the trackpad, interfering with the click mechanism and sometimes preventing clicks from registering at all.
We confirmed the battery was the source of the problem by observing the extent of the bow — it had already pushed the base panel several millimetres out of plane. The trackpad itself was undamaged; the problem was entirely mechanical pressure from the swollen cell.
Battery swelling of this kind is not caused by any fault on the part of the user. It is a known degradation pattern in the lithium polymer cells used in MacBook Pros of this generation. The cells degrade over time through normal charge cycles, and a proportion swell as they age. Apple acknowledged the fault pattern in the 2015 13-inch model through a replacement programme, and the behaviour extends to adjacent generations.
How We Fixed It
Swollen lithium polymer batteries require careful handling. The battery in the A1708 is adhesively bonded to the internal chassis — it cannot be simply unscrewed and lifted out. Forcing a swollen battery risks puncture, which can cause a thermal runaway event.
We carefully depressurised the battery cells using approved techniques before releasing the adhesive strips progressively. Once the battery was safely removed, we confirmed the trackpad assembly beneath was intact and undamaged by the pressure — no secondary parts were required.
A compatible OEM-specification replacement battery was fitted and the adhesive secured correctly. Before sealing the machine, we ran an initial charge cycle check to confirm the new battery was reading correctly in the system.
The base panel was refitted and the machine was tested across all functions: battery state of charge, trackpad click sensitivity and surface tracking, keyboard, screen, and charging via USB-C.
The Result
The MacBook Pro was returned to the Putney customer the same day. The trackpad responded correctly across the full surface. The base panel sat flat. The battery reported correctly in System Information. The machine was safe to use and charge.
Why This Happens on This Generation
The 2016–2019 MacBook Pro lineup uses a thin, flat battery design that maximises capacity within a very slim chassis. The trade-off is that the cells have less room to expand as they age. In warmer conditions — a MacBook used in a south-facing home office, or left in a warm car — degradation accelerates. Machines kept plugged in continuously without allowing the battery to cycle also tend to show this fault earlier.
The bottom panel bowing outward is the visible warning sign that the battery has swollen to a point where action is needed. At this stage the machine should be used with caution and not left unattended while charging. A battery that has swollen enough to distort the chassis is past the point where normal use is safe.
Prevention Tips
- If the base of your MacBook is bowing or the trackpad becomes stiff or unresponsive, stop using the machine until it can be assessed — do not attempt to force the panel flat or press down on the trackpad
- Avoid leaving the MacBook charging continuously without allowing the battery to discharge periodically — full-time mains use accelerates cell degradation
- Keep the MacBook out of direct sunlight and away from heat sources during charging — lithium polymer cells degrade faster at elevated temperatures
- MacBook Pros from 2015 to 2019 are the generations most commonly affected; if yours is in this range, periodic checks are worthwhile as the machine ages
Local Help in Putney SW15
We carry out MacBook battery replacements at our Putney workshop on Lower Richmond Road. Customers in SW15 can drop in directly, and free collection is available across South West London for customers who cannot travel.
Related Services
- MacBook Repair — hardware and battery repairs for all MacBook models
- MacBook Repair in Putney — local service for SW15 customers
More Case Studies
- MacBook Pro A1708 motherboard and trackpad data recovery — more complex repair on the same chassis generation
- MacBook Air liquid damage repair in Wandsworth — another common MacBook fault from a nearby area
- Faster, safer MacBook Air upgrade to latest macOS — software service restoring a MacBook to reliable use