User level: Level 1 (7 points)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
Posted on Sep 18, 2026 12:14 PM
User level: Level 9 (74,110 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.
User level: Level 1 (7 points)Sep 18, 2026 9:20 PM in response to WheelieNick
yes, thank you! after updating to macOS 27 it worked!
User level: 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?
Originally posted at discussions.apple.com/thread/256359984