Tried to obtain the web lock from a thread other than the main thread or the web thread. Crashing now

Question

bool _WebTryThreadLock(bool), 0x8053ce0: Tried to obtain the web lock from a thread other than the main thread or the web thread. This may be a result of calling to UI

Answer 1

This may be a result of calling to UIKit from a secondary thread. Crashing now...

...and as far as I can see that's just what you're doing. You're calling [alertProgress dismissWithClickedButtonIndex:0 animated:YES];, a UIKit method, from a thread other than your main thread(s), which is not allowed.

For a very straight forward way to call back to the main thread if you can't use GCD, take a look at DDFoundation.

Your code would in that case only change to do;

[[alertProgress dd_invokeOnMainThread] dismissWithClickedButtonIndex:0 
                                       animated:YES];