How to prevent present modally an active controller?

There may be another case:

Is the target ViewController presented after some user click on a button? The user may be clicking twice, making two operations and opening the same ViewController twice, if you have a shared instance of the said ViewController.

Try disabling the button while the operation is in progress, display a progress indicator, and so on.

I have found kind of solution for this

- (IBAction)menuButtonPressed:(id)sender
{
    [self.parentViewController presentViewController:self.menuAlert animated:YES completion:nil];
}

Alert view sometimes appears on menuVC, but it doesn't crash application and work normally. Answer was found there: Warning :-Presenting view controllers on detached view controllers is discouraged

I think u will need to dismiss the LAST viewcontroller first before going back by present modal segue, the viewcontroller is active, so it crash:

Use this after call segue from mainVC or something u wanted to go back:

[self dismissViewControllerAnimated:NO completion:nil]

or

[[self presentingViewController] dismissViewControllerAnimated:NO completion:nil]

or use push segue, it auto add a back button that automatically add back function