I'm using Xcode 7.0, OSX 10.10.5, and on one project IB has crashed over 20 times today. It happens as I am adjusting constraints.
Each time the error is "internal error. Setting empty vector for variable UILabel", but the label isn't always the same one.
The error is not exactly reproducible; after restarting I can do the same action and continue for a few minutes before the next crash...
The storyboard is very simple. The view I'm working on has only 6 labels and one button, and stack views.
The crashes started around the time I started using stack views and size classes.
I filed a bug report (22858326), but it would be great if anyone had any advice for avoiding this error.
TI have the same problem, i was trying to migrate to stack view, so i make a sample story board, and drop some controls, mustly buttons and labels on some stack views. Xcode crashed about 20 times in an hour with "internal error" fill out a bug report, I did (23174882). The worst part been after the crash, Xcode trying to open the same project on restart and crashing again. Apple came back with duplicate bug report. So i figure we are not the only ones having this issues. I try to find some more info, with no luck, so i suppose all I can do know is keep my layout, with out using stack view until this issue is corrected by apple.