NSUserDefaults errors in logs

if you suffer this problem when you try to save data to extension APP by using userDefault,maybe you had written this code : [[NSUserDefaults standardUserDefaults] initWithSuiteName:@"group.xxx.com"];,this code reset default userDefault. Actually,the correct code is : [[NSUserDefaults alloc] initWithSuiteName:@"group.xxx.com"]; http://www.jianshu.com/p/e782104c3bc3

I was getting a similar error:

[User Defaults] attempt to set <private> for key in <private> in read-only (due to a previous failed write) preferences domain CFPrefsPlistSource<0x1700f5f80>

but it only happened when I was plugged into Xcode.

A device reboot fixed this.

Lot of people are finding this issue on Xcode 8.

"As crazy as it sounds try rebooting phone and host, sometimes Xcode can get stuck for sum reason only restart helps.

build with Xcode 8.1 Beta and you will see the same warning, but you will also get the value. "

reference : https://forums.developer.apple.com/thread/51348