High CPU on macOS 26 During iOS Simulator Runs (Xcode 26.x, iOS 26.x): ReportCrash Flood from Repeated Simulator Crashes

I'm on macOS 26, and I've seen some serious CPU usage peaks on my mac during iOS development.

1. macOS: 26.0 or 26.1 to 26.1 to 26.x
2. Xcode: 26.0+ (also occurs at 26.2 beta as of November 11, 2025)
3. iOS simulator runtime: 26.x

 

 

My MacBook (MacBook Pro 16,1) has a MacOS 16-inch older Intel Core i9-9980HK 2.40GHz (8core 16thread), AMD Radeon Pro 5300 (4gb), and two 16GB RAM. I'm using a 512GB SSD.





what I observed
Development in iOS 26.x simulator is so slow that it can barely be developed.

The activity status view app shows that the ReportCrash process is consuming a huge amount of CPU. 
207.9%??? No, it's so funny that it can exceed 100% in seconds 🤣 

 

• If you look at the console app, you'll see a lot of crashes, and these crash errors will eventually trigger the ReportCrash process.
  MercuryPosterExtension crash reports are often more than 10 per minute.

 

 

I didn't want to know what that was at first...
The name was the same as the simulator (25B78) I installed.
And I was able to confirm that Crash did not occur when I exactly finished Xcode.



 

I've been looking through tons of tweets and reddit, but there's no workaround,
Even the latest MacBook M5 found the same symptoms..

I could see that Apple wrote the Xcode in a really weird way.


Apple Developers Can't Feel Their Computers Are All MAXs? 🤣
I'm a little jealous.. 🥹

 

 

 

 

 

Simple workaround: eventually, you need to turn off the report.

reportCrash disabled

sudo launchctl unload -w /System/Library/LaunchDaemons/com.apple.ReportCrash.Root.plist

 

For those of you who want to reactivate it

 

sudo launchctl load -w /System/Library/LaunchDaemons/com.apple.ReportCrash.Root.plist

 

 

 

I'd like to offer my boring consolation to the developers who made it this far...

App development, fighting!!