XCode 8.1 Xib editing extremely slow and completely unusable. HELP!

I'm experiencing the same problem, on both my Macbook and Mac Pro. XIBs are, ostensibly, uneditable when opened with the interface editor. XIBs can be edited when "open as -> source code" fine, but loading the interface builder locks up all XCode UI on my laptop for nearly 30 seconds and makes my Mac Pro unusably laggy.

I've also tried clearing derived data, updating cocoapods, cocoapods projects, ran cleans - seems to effect all projects, including one freshly pulled down from BitBucket. Interface Builder was completely normal in XCode 8.0, but as of updating to 8.1 somehow destroys Xcodes ability to interact with the mouse UI layer.

Other applications fuction normally when the error occurs, CPU usage for XCode is high during the XIB caused slowdown, about 40-60%, similar to JasonGreen; however XCode runs CPU usage of 150-250% during an "Analyze", during which XCode and the UI remain fully responsive, so it's not a matter of limlited CPU ability.

Honest, it feels like some XIB processing task is trying to run on XCodes UI thread...

Anyone have a fix? I don't see widespread panic, so presumably this is only happening with certain library/category/compiler flag/ect...

Same here. Went for lunch today and when I came back I noticed my macbook had decided to update XCode to 8.1. It is almost impossible to get work done now. I'd very much like to throw my macbook at the next wall. However I'm not ready to give up magsafe just yet... :/

Yes the lastest version is making the performance very slow, it suppose to run faster with every update.

Mac OS 10.12.1

Xcode 8.1

iMac Late 2015

8GB RAM

300 GB Free Space

Just got a temporary fix from Apple that works:

"You can temporarily work around the issue by changing Simulated Metrics > Top Bar to None in the view inspector at the top level."

Thanks. Changing the Status Bar and Top Bar to "Inferred" worked for me.

Changing the Status Bar and Top Bar to "Inferred" or "None" it's worked for me.

I have the same issue. I know that it will not change anything but we are just humans and I have to say that I'm really scared where Xcode development quality aims. We can read everywhere repetitive words how developer become more and more disappointed using Xcode on daily basis. Please Apple consider it and try to focus less on features and more on bug fixes and performance. It will be the biggest feature for us as a community.

Xcode 8.2.1 on macOS Sierra 10.12.3 and this is still a problem 😠

Now the work-around seems to be setting the Simulated Metrics Size to "Freeform".

Frustrating!

Same here, latest Sierra and Xcode 8.2.1, still a bug.

Reseting both Status bar and Top bar to None resolves the usability issues.

I can only imagine now one at Apple is using IB. It's impossible to do anything in XIB file with the corresponding settings.

Looking at processes, Xcode is up to 100% on one core and launchd_sim is taking 45% of another one (with the problematic settings)

I have Xcode 8.3 and had this same problem. All solutions above didn't work for me. The only thing that worked for me was...

1. Create a new storyboard and save
2. Quit Xcode
3. Open Main.storyboard in plain text editor
4. Copy and paste the <scenes> tag and everything in it to the same place in the new storyboard
5. Open Xcode
6. Select the new storyboard
7. Save the storyboard

This finally worked for me after too much time lost because of this nonsense.

I had this same problem on Xcode 8.3.3. Storyboard was very slow suddenly.
In my case I have setted the Simulated Metrics Height to 667,5.

Bug fixed when I change back to 667.

Unfortunately, this does not work in Xcode 9.0.1, Sierra 10.12.6