I want Xcode to stop downloading the files in ~/Library/Developer/Xcode/iOS DeviceSupport/12.4 where 12.4 is the iOS version of my iPhone. I have deleted them a couple of times now.

I also want to be able to connect my iPhone via USB to the Mac, without the fear of 2.5 GB bandwidth and storage cost.

This setting in Xcode Preferences → Components doesn't list 12.4.

enter image description here

Xcode 10.3, iOS 12.4, macOS 10.14.

These posts talk about removal only:

3 Answers 3


The screenshot you showed is for iOS simulator runtimes. The data you are asking about is the dylib cache for your iPhone, which Xcode copies from the device. If you don't want to use that device for development, select it in the Devices Window in Xcode and deselect it as available for development. That should prevent it from being used for development in the future.

  • I put the screenshot as an attempt to solve the problem.. I didn't know what it does is why the question exists. :) Also, would other devices like iPad which also list iOS 12 as their OS affect this.
    – anki
    Commented Jan 18, 2020 at 20:38

Looks like it wasn't downloading the thing, I checked in activity monitor after deleting the folder. It copies it from somewhere else, most likely


Xcode simulator constantly download something

  • I removed all the listed items from Xcode's Window Menu → devices and simulators, which listed iOS 12 as their OS version.
  • Went to iOS settings → Developer and cleared paired devices.

  • Connected iPhone, unlocked it and chose "Don't Trust" upon prompt.

No more unnecessary folders.

Since it causes problem for iTunes backup and network sharing, Go to /Users/ankitkumar/Library/Developer/Xcode/iOS DeviceSupport/12.4 right click on it > get info > Check locked.


Temporary solution!

rename the file com.apple.nsurlsessiond(Dont delete) in


to something -com.apple.nsurlsessiond

and also the file nsurlsessiond(Dont delete) in


to something -nsurlsessiond

Apps with admob works perfectly also no problem with safari

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