Unable to complete data transfer from iPhone 15 Pro Max to 17 Pro Max

Question

Poppy24_ Author

Level 1

12 points

Unable to complete data transfer from iPhone 15 Pro Max to 17 Pro Max

iPhone 15 pro max to 17 pro max, both 512gb

I have ample storage left on phone and on iCloud

tried to do data transfer wirelessly at least 5 times, and by wire 3 times.

both are ios26, charged, connected to home wifi, and untouched placed next to each other on a proper table.

about 30min -1h left on the transfer, iPhone 15promax, or both phones will show “unable to complete data transfer”

ialso tried via iCloud backup, but somehow unable to backup my phone. “ some files were unavailable during the last backup”.

i have reset network settings, done a reset on both phones.

i have been trying for the

last 26 hours. Please help :(

[Re-Titled by Moderator]

Original Title: Unable to complete data transfer

iPhone 15 Pro Max

Posted on Sep 20, 2025 2:11 AM

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Answer 1

LD150

Level 10

100,155 points

Sep 20, 2025 2:43 AM in response to Poppy24_

Try setting up the 17 without quickstart, use the 15's backup instead. Use a good wifi not cellular .

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Answer 2

Poppy24_ Author

Level 1

12 points

Nov 5, 2025 3:26 PM in response to lexorious

No :( I went to Apple Store and the Genius-es were telling me other people had the same issue with the new 17 too :(

I was at the store for about 5 hours trying to do the backup with Support. I even tried with the Apple Thunderbolt cable as I saw online that it’s faster and would help a regular transfer.

Staff told me perhaps there is a corrupted file in the old phone. In the end, I just started my phone as a new phone, but as I was logged into iCloud, the contacts, photos were transferred. I had the honor (and pain) of redownloading every single app and rearranging them, and reselecting lock screen pics.

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Answer 3

Poppy24_ Author

Level 1

12 points

Sep 20, 2025 3:44 AM in response to LD150

Hello! Thanks for helping - yeah as mentioned I’m on WiFi.. unfortunately there is an error for 15’s backup and I’m not able to backup onto iCloud as well — “some files were unavailable during the last backup”

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Answer 4

LD150

Level 10

100,155 points

Oct 31, 2025 1:33 PM in response to Poppy24_

Poppy24_ wrote:

Hello! Thanks for helping - yeah as mentioned I’m on WiFi.. unfortunately there is an error for 15’s backup and I’m not able to backup onto iCloud as well — “some files were unavailable during the last backup”

What error is preventing you making a new backup to iCloud?

It may be preventing quickstart too.

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Answer 5

Nov 5, 2025 2:55 PM in response to Poppy24_

For the last five days I have been trying to clone this POS 17 Pro Max. I tried everything, as always, MacBook encrypted backup, Wi-Fi method, USB Thunderbolt 4 cable, and nothing works. Both the 15 Pro Max and 17 Pro Max are on iOS 26.1, and I even did a DFU reinstall of iOS 26.1 on the 17 Pro Max. The MacBook costs 3000€, the 17 Pro Max is 1600€, Unacceptable.

Both phones are 512 GB, and the old one still has 200 GB free.

[Edited by Moderator]

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Answer 6

Nov 6, 2025 3:45 AM in response to lexorious

I don’t think even Apple knows the solution, except for doing a fresh start without data transfer. Shame. Such expensive devices and an entire ecosystem, and it still doesn’t work. I’d expect this from cheap Android trash paired with a bargain Windows laptop, not from an Apple combo.

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Answer 7

Oct 31, 2025 1:08 PM in response to Poppy24_

Hi there, I have the same phones with issue (just bot are 256GB).. did you manage to find a solution for this? please let me know

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