SwiftData not loading under iOS 26.1

Updated the phone to iOS 26.1 and now the app is not working anymore, even previously approved version published on App Store which works perfectly on iOS 26.0.1, and iOS 18+.

I deleted the app from the phone and installed fresh from App Store, still the same.

Logic is that on start app copies previously prepared SwiftData store file (using the same models) from app bundle to Documents directory and uses it. Currently app just hungs with loader spinner spinning as it can t connect to the store.

Getting this error in console when running from Xcode on real device with iOS 26.1 installed: CoreData: error:

CoreData: error: Store failed to load.  <NSPersistentStoreDescription: 0x10c599e90> (type: SQLite, url: file:///var/mobile/Containers/Data/Application/DA32188D-8887-48F7-B828-1F676C8FBEF8/Documents/default.store) 
with error = Error Domain=NSCocoaErrorDomain Code=134140 
"Persistent store migration failed, missing mapping model." 
UserInfo={sourceModel=(<NSManagedObjectModel: 0x10c503ac0>) isEditable 0, 
entities { /// there goes some long models description
addPersistentStoreWithType:configuration:URL:options:error: returned error NSCocoaErrorDomain (134140)

Any help or workaround will be greatly appreciated.

That is a migration error, which happens when you change your SwiftData models in a way unsupported by lightweight migration.

You can probably start with reviewing the changes you made on your SwiftData models, if any. For more information about how to evolve your SwiftData schema, see this WWDC session.

Best,
——
Ziqiao Chen
 Worldwide Developer Relations.

SwiftData not loading under iOS 26.1
 
 
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