How do I fix 'Developer Disk Image Could Not Be Mounted' error on iPhone 18 Pro Max with Xcode?

Question

Level 1

7 points

How do I fix 'Developer Disk Image Could Not Be Mounted' error on iPhone 18 Pro Max with Xcode?

I need help. I bought the iPhone 18 pro max today and enabled developer options, and trusted my Mac. but when I wanted to build and run an app ive made in Xcode to my iPhone I got an error "the developer disk image could not be mounted on this device". I have never seen this error and I had no problems exporting apps to my iPad or old iPhone before. can anyone tell me how to fix it?

[Re-Titled by Moderator]

Original Title: Xcode error

MacBook Air 13″, macOS 26.5

Posted on Sep 18, 2026 12:14 PM

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Answer 1

WheelieNick

Level 9

67,250 points

Sep 18, 2026 12:48 PM in response to Alex_44

To fix the "Developer Disk Image could not be mounted on this device" error on your brand new iPhone 18 Pro Max, you primarily need to ensure that your version of Xcode completely supports the new device architecture and its corresponding version of iOS.

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Answer 2

Alex_44 Author

Level 1

7 points

Sep 18, 2026 9:20 PM in response to WheelieNick

yes, thank you! after updating to macOS 27 it worked!

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Answer 3

6510

Level 1

28 points

Sep 21, 2026 11:12 AM in response to Alex_44

I have an Intel MacBook Pro and have set up Xcode Cloud to build apps for the iPhone 18. How do I get the .ipa on the device with the "Developer Disk Image Could Not Be Mounted" error?

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