A tip to reduce keyboard lag
Symptom: There is a noticeable delay between text input using the virtual keyboard and its appearance onscreen.
This fix seems to work for some users: Go to Settings --> iCloud and turn off Documents & Data.
Another suggested repair is to navigate to Settings --> General --> Reset and then choose Reset All Settings.
Wi-Fi and Bluetooth problems
Symptom: Some users have reported problems using Wi-Fi and Bluetooth after the iOS 7 update. These may appear grayed-out in Settings and won't toggle back on. Or if you do switch them on, they switch themselves off again.
A quick solution is to restart your iPhone and your Wi-Fi router. If this doesn't permanently fix the problem, additional suggestions from Apple's Discussion Forums include: Put the iPhone into Airplane mode and reset your network settings (go to Settings --> General --> Reset --> Reset Network Settings). After that's done, turn off Airplane mode.
Motion sickness (yes, motion sickness)
Symptom: There were early reports that some users experienced motion sickness symptoms while getting accustomed to iOS 7's new parallax effect. That's the effect that appears to make the background image move independently of the app icons floating on a different virtual plane. It's most noticeable when you tilt the device while looking at the home screen. (Note: Older devices like the iPhone 4 don't have this option.)
If you navigate to Settings --> General --> Accessibility, you can choose from several options that might help alleviate any motion sickness from iOS 7.
If iOS 7 is making you nauseous, you can minimize the parallax problem easily:
First, try the Accessibility options (navigate to Settings, then General to get to it) and select Reduce Motion.
If that's not enough, in the same place -- Accessibility -- you can select Increase Contrast to make text easier to read.
Finally, if you navigate to Settings and then choose Wallpapers & Brightness, make sure to choose a Stills image as your background wallpaper.
What to do if iTunes crashes or fails to launch
Symptom: Some users are finding the iTunes app fails to launch, or crashes when they try to open it.
Open the Music app and tap Store in the upper left corner. iTunes should open up. In the future, the app should launch correctly. (Some iOS 7 users have found that this problem creeps up again, so the fix may not be permanent.)
One potential cure for iTunes crashes is to make sure it's not open in the background (open the multi-tasking view and swipe the iTunes app to the top of the screen), then sign out and sign back in with your Apple ID.
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