By removing code and trail and error, I found the following line in my .xib file crashes ibtool in Xcode 6.3.1.
<fontDescription key="fontDescription" style="UICTFontTextStyleHeadline"/>
Within the following block:
<navigationController id="9" customClass="CustomNavigationController">
<extendedEdge key="edgesForExtendedLayout"/>
<simulatedStatusBarMetrics key="simulatedStatusBarMetrics" statusBarStyle="blackOpaque"/>
<simulatedNavigationBarMetrics key="simulatedTopBarMetrics" translucent="NO" prompted="NO"/>
<navigationBar key="navigationBar" opaque="NO" clipsSubviews="YES" multipleTouchEnabled="YES" contentMode="scaleToFill" barStyle="black" translucent="NO" id="11">
<autoresizingMask key="autoresizingMask"/>
<color key="backgroundColor" white="0.33333333333333331" alpha="1" colorSpace="calibratedWhite"/>
<color key="tintColor" red="0.52042670701978977" green="0.78835227272727271" blue="0.33819077917403134" alpha="1" colorSpace="calibratedRGB"/>
<textAttributes key="titleTextAttributes">
<fontDescription key="fontDescription" style="UICTFontTextStyleHeadline"/>
<color key="textColor" white="1" alpha="1" colorSpace="calibratedWhite"/>
</textAttributes>
</navigationBar>
<viewControllers>
<viewController nibName="RootViewController" id="13" customClass="RootViewController">
<extendedEdge key="edgesForExtendedLayout"/>
<navigationItem key="navigationItem" id="14">
<nil key="title"/>
</navigationItem>
</viewController>
</viewControllers>
</navigationController>
Is there another way to get the same functionality without crashing ibtool. This project is fairly old, is something I'm doing obsolete?