Xcode IB Stupid Warning - xcode

Question

Once again Xcode IB frustrates developers with unnecessary warnings: I cannot seem to get remove this warning from my Xcode project.
When double clicking the warning it brings up my MainMenu.xib file but gives no reference to what is causing the issue. Any ideas?
EDIT:
I've stripped down much of my .xib for public viewing but still have the error with very few objects. You can find the file here: https://www.dropbox.com/s/r2piuojr86dhlt9/MainMenu.xib?dl=0

Answer 1

This is a warning shown starting from Xcode 7 when UI elements like a label or table view column header use a font style or variation that is on available on older OS (and of course your project is still targeting them).
In my project a table view column header was using system font with "medium" font style variation instead of regular on a project targeting OS X 10.9+.
The weird thing is I had to restart Xcode as Interface Builder refused to change the style of the control. Possibly a small glitch of this early 7.0.1 Xcode version.
Anyway, either setting every control style to Regular or changing your project target to 10.11 should fix the warning.

Answer 2

Once again Xcode IB frustrates developers with unnecessary warnings.
Felt the same way about it too, until I saw how my typography differs in 10.10 compared to 10.11. One thing is true – the message is rubbish without pointing to a problematic storyboard item, see P.S section of the post for a semi-workaround.
Current answer almost gets it, but problem is not with font styles being unavailable in older targets, it's with Xcode not handling them properly, see full blog post for details.
If you want to keep your styles, use custom textfield with custom inspectable property. Open up identity inspector and set custom class to TextField, preferred font weight attribute will show up in attribute inspector, set the required value, build and enjoy the result.
import AppKit
#IBDesignable public class TextField: NSTextField
{
#IBInspectable public var preferredFontWeight: Int = 0
override public func awakeFromNib() {
if #available(OSX 10.11, *) {
return
}
guard
let weight: Int = self.preferredFontWeight where weight > 0,
let font: NSFont = self.font,
let name: String = font.familyName,
let manager: NSFontManager = NSFontManager.sharedFontManager() else {
return
}
// Full details here – https://developer.apple.com/library/mac/documentation/Cocoa/Reference/ApplicationKit/Classes/NSFontManager_Class/#//apple_ref/occ/instm/NSFontManager/convertWeight:ofFont:
//
// 1 – ultralight
// 2 – thin
// 3 – light, extralight
// 4 – book
// 5 – regular, display
// 6 – medium
// 7 – demi, demibold
// 8 – semi, semibold
// 9 – bold
// 10 – extra, extrabold
// 11 – heavy
// 12 – black
// 13 – ultrablack
// 14 – extrablack
if let font: NSFont = manager.fontWithFamily(name, traits: manager.traitsOfFont(font), weight: weight, size: font.pointSize) {
self.font = font
}
}
}
If you don't really care about the styles, use regular weight font for all text, it should solve the problem, see my earlier answer for available options.