Photos app crashing while accepting invite for Shared Photo Library

Given that the problem persisted across phones, your friend should probably seek professional help from Apple Support personnel. They may need to reset something deep in the invitation-passing mechanism or her iCloud library.

Out of curiosity, how full was her iPhone 11 storage, compared with the size of her husband's shared library? The "Optimize iPhone Storage" option can achieve pretty amazing ratios on initial connection, but it does require some initial storage. The extra storage on her new iPhone 16 should have been plenty for any but the most gargantuan shared library with optimization active.

I have seen the same but unfortunately I can not provide a fix.

A few months ago I finally decided to start using iCloud Photos and got 2 TB subscription hoping to bypass the historically flaky USB Photos sync to iPad. But inviting family members to iCloud Photo sharing was IMHO not a good user experience either.

And, maybe similar to your experience, in one user's iPhone 15 iOS 18 accepting the invitation screen repeatedly just vanished despite logging out/in iCloud and rebooting the iPhone. The next troubleshooting steps would have been a forced reboot, or reset settings, or finally backup, reset factory settings and restore, but the owner of that iPhone did not want to do that.

Anyway, some family members also had too old Macs running Big Sur and Monterey which do not support shared albums like Ventura and later do, so I downgraded iCloud to 200 GB, and reverted using the local (historically flaky...) USB Photos sync to iPad.

I have the same issue. Both on my iPhone 13 and my 2023 Macbook with the latest OS versions, the Photos app crashes upon accepting a family members shared album invite. We are on the same iCloud+ plan and 2 other family members had no issues.

Sadly neither iOS 18.6 nor MacOS 15.6 fixed the issue for me

Have u already solved this issue?If so please tell me how to fix it,i have the same issue. thx