I was getting this stack dump, which made it difficult to work out what the problem was.
android.content.res.Resources$NotFoundException: Resource ID #0x7f060056 at android.content.res.Resources.getValue(Resources.java:1123) at android.support.v7.widget.AppCompatDrawableManager.loadDrawableFromDelegates(AppCompatDrawableManager.java:328) at android.support.v7.widget.AppCompatDrawableManager.getDrawable(AppCompatDrawableManager.java:193)
Problem was fixed by moving 2 vector drawables (used in menu) from drawable-v24 to drawable.