Is your iPhone acting sluggish? Do apps begin to open and then suddenly you’re back on the home screen? Having trouble sending or receiving email?
If you’re seeing several different problems, don’t suspect viruses or malware. It’s more likely that you are running out of storage space on your phone.
But before you check that—
Restart the iPhone
First, turn the phone entirely off (press and hold the Home button until you see the slider) and then back on again. Most of us run our phones for weeks without restarting, but simply restarting the phone clears some settings and resets things. If this simple fix stops the “weird” behavior of your iPhone, then there’s no need to worry about what caused the problem.
Is Your iPhone Full?
If the problem returns, then check to see how full your phone’s storage is. Completely (or even nearly) full storage can cause different and changing problems, from slowness to crashes. To check your storage in iOS 9, open the Settings app and select Storage & iCloud Usage and look under the STORAGE heading. You should see Used and Available. Aim to keep Available storage to about 2 GB.
To see what apps are using your phone’s storage, tap “Manage Storage” under the STORAGE heading, and your iPhone will generate a list of apps and their use of data storage, starting with the largest at the top of the list. Tap on an app to get more information about the app and to delete it and its data (except for Apple’s core apps, like Photos, which cannot be deleted).
Too Many Photos and Videos: iCloud Photo Library
The most likely culprit of a full iPhone is Photos & Camera, and that will require a different fix. The easiest thing to do is to start using iCloud Photo Library to manage your photos. Apple has created this service to automatically upload all of your photos to iCloud and to intelligently manage what photos stay on your device so they don’t take up too much space. If you have iCloud Photo Library turned on for this device, then Photos & Camera shouldn’t be the source of your lack of space (unless you’ve been taking a lot of photos without access to wifi).
But before turning iCloud Photo Library on, make sure you understand it and are prepared to buy additional iCloud storage space if you need it. A good place to start is Apple’s iCloud Photo Library support page: https://support.apple.com/en-us/HT204264.
Too Many Photos and Videos: Delete ‘Em
If you don’t want to use iCloud Photo Library, you can manually remove photos and videos from your device. There is no quick way to delete all your photos at once, but you can select entire “Moments” to delete each as a group. A faster way to delete images is to connect your iPhone to your Mac and use the built-in utility called Image Capture to select and delete the photos.
Here’s an older article that includes how to do this on Windows:
Delete All Photos from iPhone At Once
Photos and Videos Hiding on Your iPhone
You may also find that Messages is taking a lot of storage space because of the photos and videos you’ve received. In Messages, you can delete entire conversations or you can delete individual photos and videos. (Tip: if you want to save a particular image or video, tap and hold it (or Force-Press if you have an iPhone 6 or later) and select “Save” on the pop-up menu).
Also, any app that can take photos (scanning apps, for example) can take up a lot of storage. Either delete the entire app and all its data, or ope the app and delete individual photos and videos.
Still Running Out of Storage?
Of course, it is possible that something has gone wrong with your phone’s software and something else is filling up your storage. If you can’t figure out what’s eating the storage, it’s time for a trip to the Genius Bar. Or contact me.
Note: Specific instructions (menus, navigation) in this article refer to iOS 9 and may not be valid in other versions.