IOS – Does a force restart in iOS do anything different from a normal restart

iosrestart

I'm presenting a talk on troubleshooting OS X and iOS for a Mac user group next month, and I was surprised to hear that several members thought a "hard reset" or force restart of an iPhone or iPad is a useful troubleshooting procedure. They suggested that it does some sort of clearing of caches or resetting of [insert hand waving here] which is different from simply shutting the device off and turning it back on.

I've searched pretty deeply across Apple's support site, the Apple discussion forums, the popular Apple news websites, and sites offering Apple tech tips and I haven't found any corroboration.

To clarify the answer I'm seeking, I'm particularly looking for firsthand knowledge (i.e. "Apple told me a force restart does foo") or a published reference that confirms one way or the other.

Best Answer

A force restart is at the hardware level, not the software level. This means that even if iOS is completely frozen or in a different mode altogether (such as DFU Mode, Recovery Mode, or Restore Mode), you can still perform a force restart. It does nothing more than cut the power and turn the device back on again. This means that it doesn't clear any caches or reset anything. A regular restart actually does more than a force restart.

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Yeah, ok. I can solve this with Applescript. Thanks to patrix for getting me to look in the right direction.

tell application "Finder"
    restart
end tell

Saved as restart.scpt, run with osascript restart.scpt. I've tested running it remotely with the screen locked, and it restarted cleanly perfectly. I need to remember that Applescript exists whenever I want to automate Finder interactions..

Mac does not restart, shutsdown instead

Since you didn't list enough technical details about how file vault is set up (for instance if you have auto log in enabled or disabled, whether you are using institutional keys or just having one or more users storing the unlocking keys in the user accounts so that the recovery HD can unlock things) - I'll start with some steps to narrow down what might be happening.

First thing is to check if the machines are capable of restarting by storing the file vault key in RAM:

fdesetup supportsauthrestart

If that reports "false" then your hardware might not support restarts with FileVault 2 enabled. If it's true, does the system reboot if you ask for a controlled restart?

fdesetup authrestart

Also, if you're not comfortable with the fdesetup tool, you might want to review some of the helpful articles from Rich Trouton's blog. You'll want to start with an old article getting the basics covered if the current articles assume too much knowledge of how fdesetup works as dealing with file vault from the command line is a lot like the proverbial "sip of water from a fire hose" to many.

Best Answer

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Mac does not restart, shutsdown instead

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