A phone that restarts on its own — once — is usually nothing to worry about. A phone that restarts repeatedly throughout the day is telling you something is wrong. Here's how to work out what's causing it and what to do about it.
This is the most common cause of random restarts, especially on phones that are a few years old. When a battery degrades, it struggles to deliver a steady current under load. The phone interprets a sudden voltage drop as a power failure and restarts itself to protect the hardware.
If your phone also drains faster than it used to, gets warm during normal use, or the battery percentage jumps around unpredictably, the battery is very likely the culprit. A battery replacement is a quick fix — usually done while you wait — and in most cases completely stops the random restarts.
Phones shut down and restart when they get too hot — it's a safety feature built in to prevent damage to the processor and battery. If the restarts happen when you're gaming, streaming video, or using the phone in direct sunlight, overheating is the most likely cause.
Give the phone a rest in a cool, shaded spot and see if it settles. A case that traps heat can make this worse. If the phone overheats during light tasks like browsing or calls, that points to something more serious — an app running out of control in the background, or a hardware fault generating excess heat.
A single badly coded or corrupted app can crash the whole system and trigger a restart loop. If the restarts started around the same time you installed or updated an app, that app is the likely cause. Try uninstalling recently added apps one at a time and see if the restarts stop.
You can also check which apps are using the most resources. On Android, go to Settings → Battery → Battery Usage. On iPhone, Settings → Battery shows which apps are consuming the most power — a runaway app often shows disproportionately high usage.
When a phone's storage is nearly full, the operating system can't manage memory properly and becomes unstable. Crashes and restarts are a common result. If you're running on less than 1–2GB of free space, clearing some storage — photos to the cloud, unused apps deleted — can resolve the issue entirely.
Sometimes a failed or interrupted software update leaves the operating system in an unstable state. Check if there's an available update in your phone's settings and install it. If an update won't complete or keeps failing, that itself can indicate a deeper storage or hardware issue.
If the phone was dropped, exposed to water, or received an impact, internal damage can cause random restarts. A loosened battery connector, damaged charging circuit, or a failing component on the board can all produce this symptom. If none of the software-side fixes work and there's a history of damage, it's worth bringing it in for a diagnosis.
If the restarts are frequent, getting worse, or paired with other symptoms like the phone getting very hot, battery draining rapidly, or the phone not charging properly — bring it in. We'll run a free diagnosis and tell you exactly what's wrong. For most cases (a worn battery being the most common), it's a straightforward same-day repair.
We're at 82 High Street, Yiewsley, UB7 7DS — open Monday to Saturday 9am–8pm, Sunday 9am–7pm. No appointment needed, just walk in.
We'll tell you exactly what's causing it before any work starts. Walk-ins welcome, 7 days a week.