It's happened to the best of us: the display on your iPhone or iPad suddenly freezes and - no matter how hard you try - won't respond to your increasingly manic finger tapping. The screen isn't working and the device is stuck, and essentially unusable.

But rest assured: most of the time it's quite easy to fix a frozen screen, and we list nine simple steps you should try in the following article.

However, for certain models of iPhone there is a bigger related screen issue that has been getting some media attention, and if this is what's causing the problem you may have more to worry about. We'll look at that problem - which has become known as 'Touch Disease' - in more depth, including how to avoid it and what to do if you experience it, later in the article.

Note that this article is about unresponsive displays. For screens that are visibly broken or shattered, read How to repair a cracked iPhone or iPad screen. We have related advice in How to fix an iPhone or iPad that won't turn on.

How to fix an iPhone or iPad screen that's not working

Tips & fixes for unresponsive screens

  • Is the screen not working all the time, or only when using one specific app? If it's the latter, try uninstalling and reinstalling the app.
  • Are your fingers wet? Dry off any moisture. Check they're clean, too - anything that could be stopping the touchscreen making a good connection.
  • Just to check, you're not wearing gloves, are you? Some gloves are designed to work with touchscreens, but most don't.
  • Try removing the screen protector, if you use one.
  • Give the screen a wipe with a soft cloth. (Read more: How to clean an iPhone screen safely.)
  • Assuming your device has this feature, check the 3D Touch sensitivity settings. Go to Settings > General > Accessibility > 3D Touch and adjust the sensitivity slider.
  • If the screen problem is related to rotation (ie refusing to rotate when you want it to, or rotating when you don't), check Orientation Lock. Swipe up from the bottom of the screen to bring up Control Centre, and tap the 'rotating padlock' icon. And try fiddling with the side switch on your device, if it has one. (This only applies to the iPad Air 1 and earlier. iPhones have never had rotation switches.)
  • Hold down the circular Home button and the On/Off (Sleep/Wake) button at the same time for around 10 seconds. This will restart the device and should restore the screen to full working order.
  • A more extreme option is to reset the device to factory settings.

If none of these tips work, it's possible your device has so-called Touch Disease (also known as Touch IC Disease), which we discuss in the next section.

Touch Disease

Back in 2016 an Apple scandal hit the headlines: Touch Disease.

The popular repair site iFixIt is responsible for identifying Touch Disease (and naming it too), although they say the issue had been around for the two years since the launch of the iPhone 6 and 6 Plus. Touch Disease is very likely an additional symptom of Bendgate - a design flaw with the iPhone 6 range of devices that meant the devices could become bent.

What is Touch Disease?

Phones affected display a small flickering grey bar at the top of the screen - about the height of the iOS menu bar. It looks a bit like old-school TV static. Additionally - or alternatively - the screen may become completely unresponsive to touch.

The problem can be intermittent, with some users saying that it appears when they first wake their devices but then goes away after a minute or so. Some users say applying pressure to the top screen area can fix the issue, while others say that twisting the device slightly is also a temporary fix.

Here at Macworld we DO NOT recommend you try either of these techniques because you could make the problem worse or break the phone entirely.

Which phones are affected by Touch Disease?

The iPhone 6 and iPhone 6 Plus are the only models affected by Touch Disease.

The successors to these models, the iPhone 6s and 6s Plus, are not affected because Apple redesigned the logic board, moving the affected components (see below), and also making the devices more structurally rigid so they're far less prone to bending.

Older phones are also not affected. The iPhone SE, launched in March 2016, is not affected because it's based significantly on the older iPhone 5s design.

An individual writing on Reddit, and who claims to be an Apple technician, said he was told by managers that the issue was fixed in models manufactured after November 2015 - although he's found phones manufactured after this date are still affected. Sites like iPhone IMEI can provide details of when a phone was manufactured, even if they're not always 100% accurate.

What causes Touch Disease - and how can I avoid it?

iFixIt spoke to various independent iPhone repair shops and came to the conclusion that the Touch IC chips on the phones' logic board break away partially, making for intermittent electrical connections. This in turn causes the above-mentioned symptoms.

In later models of iPhone the Touch IC chips are moved on to the display assembly, which is why the 6S and 6S Plus are not affected. In older phones the chips were protected via a metal shield, so again aren't affected.

Experts say the Touch IC chips break away from the board during everyday use, such as when a phone flexes slightly when stored in a trouser pocket.

This is why applying pressure to the screen, or twisting it slightly, can appear to fix the problem - it forces the Touch IC chips to re-establish full contact with the logic board. However, this is not a permanent solution and the problem will return.

Notably, Touch Disease is not an issue with the screen or its digitiser (that is, the layer beneath the screen that registers touch), and replacing the screen will not solve the issue.

Because of its larger size, the iPhone 6 Plus is said to be particularly prone to Touch Disease - and iFixIt quotes one repair expert who reckons that virtually all iPhone 6 Plus phones will be affected at some point. However, for the sake of balance we have to point out that there are literally hundreds of thousands of iPhone 6 and 6 Plus users worldwide who have never experienced the issue.

Because it's not entirely clear what causes the Touch IC chips to detach, it's also not clear how to avoid it happening. However, a tough, rigid case might be a good investment and avoiding putting the phone in a trouser pocket might also be a good idea - especially if you like to wear skinny jeans!

What to do if you're affected by Touch Disease

If your device is still within its guarantee period then take it to Apple, where they'll almost certainly either swap the logic board for a replacement, or swap the entire phone for a replacement.

Apple has addressed the issue with a statement and announced a repair programme. But the company believes the issue to be caused by a device "being dropped multiple times on a hard surface and then incurring further stress" and will charge for a repair if your device is out of its guarantee period. (We round up Apple's currently active repair and recall programmes here.)

In theory, the Consumer Rights Act here in the UK provides for getting a free repair or replacement within a reasonable time outside the guarantee period but - as Which? Magazine reports - it's a grey area and you'll probably have to argue the case.

For more advice on your legal rights, see How to get a broken iPhone repaired or replaced.

Third-party repair shops are able to re-solder the Touch IC chips to make a permanent connection, and some also apply a metal plate over the chips to stop the issue recurring. The cost is likely to be a fraction of what Apple charges.

However, a third-party repair is likely to make your phone invalid for any official product recall in future, or any other repair for which you might want to approach Apple. Additionally, it can be hard vouching for the quality of third-party repairers - one individual on Reddit reported that he had Touch Disease fixed by a third-party repair shop, but they broke the phone's GPS chip and camera while doing so.

For these reasons, we always advise taking your phone to Apple first and foremost if there's any kind of issue.

A low-fi solution reported by one Redditor is to put a coin between the back of the iPhone, just beneath the camera lens, and its case - although the case has to be of the rigid and hard variety, and not soft or floppy. This trick applies a small amount of pressure that forces the Touch IC chips to connect.

Additional reporting by Simon Jary