title: ios app crash on startup
body: <p>I started using crashlytics for my iphone app, and it seems that it crashes for some users during startup (or what I am guessing is startup). Here is the stack trace:</p>
  
  <pre><code>Fatal Exception: NSInvalidArgumentException
  -[NSNull rangeOfCharacterFromSet:]: unrecognized selector sent to instance 0x19687eba0
  Thread : Fatal Exception: NSInvalidArgumentException
  0  CoreFoundation                 0x00000001854aa59c __exceptionPreprocess + 132
  1  libobjc.A.dylib                0x0000000195bfc0e4 objc_exception_throw + 60
  2  CoreFoundation                 0x00000001854b1664 __methodDescriptionForSelector
  3  CoreFoundation                 0x00000001854ae418 ___forwarding___ + 928
  4  CoreFoundation                 0x00000001853b2b6c _CF_forwarding_prep_0 + 92
  5  UIKit                          0x0000000189fc38a0 -[UILabel _contentInsetsFromFonts] +    104
  6  UIKit                          0x000000018a13ac90 -[_UILabelLayer updateContentInsets] + 76
  7  UIKit                          0x000000018a13ad50 -[_UILabelLayer updateContentLayerSize] + 56
  8  UIKit                          0x000000018a13ae34 -[_UILabelLayer layoutSublayers] + 36
  9  QuartzCore                     0x00000001895ac564    CA::Layer::layout_if_needed(CA::Transaction*) + 320
  10 QuartzCore                     0x00000001895ac408 CA::Layer::layout_and_display_if_needed(CA::Transaction*) + 32
  11 QuartzCore                     0x00000001895abc08 CA::Context::commit_transaction(CA::Transaction*) + 276
  12 QuartzCore                     0x00000001895ab98c CA::Transaction::commit() + 436
  13 QuartzCore                     0x00000001895a53bc CA::Transaction::observer_callback(__CFRunLoopObserver*, unsigned long, void*) + 80
  14 CoreFoundation                 0x0000000185462a50 __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ + 32
  15 CoreFoundation                 0x000000018545f9dc __CFRunLoopDoObservers + 360
  16 CoreFoundation                 0x000000018545fdbc __CFRunLoopRun + 836
  17 CoreFoundation                 0x000000018538d0a4 CFRunLoopRunSpecific + 396
  18 GraphicsServices               0x000000018e52f5a4 GSEventRunModal + 168
  19 UIKit                          0x0000000189cc23c0 UIApplicationMain + 1488
  20 partybutton                    0x00000001000d6de0 main (main.m:16)
  21 libdyld.dylib                  0x000000019626aa08 start + 4
  </code></pre>
  
  <p>Not really sure how to debug this since I cannot reproduce on my own. Any pointers?</p>