Hi, You're here because your project has issues related to Xcode Previews or Swift Previews. The issue you're experiencing may be the result of any of the following: An error in your SwiftUI app, Xcode previews, or on-device previews. A configuration error in your Xcode project, including any third-party dependencies or packages. A system issue in the operating system, SwiftUI, or in Xcode Previews. Based on your request, I need more information about your SwiftUI app when rendering Xcode Previews or on-device previews. Specifically, I’ll need the diagnostics Swift Previews generates to make sure I understand the error encountered by the preview system. Please create a report in Feedback Assistant to share the details requested in the instructions below. For issues with macOS, Mac Catalyst, on-device iOS, or on-device visionOS previews, perform the following steps to gather diagnostics: Download and install the Swift Previews logging profile for your device. Reproduce the error while previewing on device, taking note of the timestamp when the error occurred. Attach the Previews diagnostics, sysdiagnose from your Mac, a sysdiagnose from the previewing iOS or visionOS device. For issues with Xcode Previews, perform the following steps to gather diagnostics: Download and install the Swift Previews logging profile for your device. Reproduce the error in Xcode Previews, if you haven’t already done so. If an error banner appears in the canvas, click the "Diagnostics" button within the banner, then go to Step 5; otherwise, continue to Step 4. If the error banner is missing, navigate to the menu in Xcode: Editor > Canvas > Diagnostics In the presented sheet, click the "Generate Report" button. Attach a zip file containing the diagnostic report to your bug report (it will be named something like previews-diagnostics-0123456789.zip). Submitting your feedback Before you submit to Feedback Assistant, please confirm the following information is included in your feedback: with the Swift Previews logging profile installed, attach the sysdiagnose logs gathered after reproducing the issue the Previews diagnostics generated by Xcode timestamp identifying when the issue was reproduced focused sample Xcode project that reproduces the issue (if applicable) screenshots or videos of the error (optional) Please include all requested information to prevent delays in my investigation. After your submission to Feedback Assistant is complete, please respond to your original Forums post with the Feedback ID. Once received, I can begin my investigation and determine if this issue is caused by an error within your SwiftUI app, a configuration issue within your Xcode project, or an underlying issue in the operating system, SwiftUI, in Xcode Previews, or on-device previews. Cheers, Paris X Pinkney |  WWDR | DTS Engineer

I’ve hit a strange SwiftUI preview crash that happens on macOS previews when using a view inside a List’s ForEach, resulting in the error Fatal Error in TableViewListCore_Mac2.swift. Only crashes macOS preview - iPhone/iPad preview doesn't crash. Doesn't crash when actually running the app. Here’s a minimal reproducible example, causing the preview to crash. XCode: Version 26.0.1 (17A400) MacOS: 26.0.1 (25A362) import SwiftUI struct Item: Identifiable { let id = UUID() let name: String } struct ItemRow: View { let item: Item var body: some View { HStack { Button(action: {}) { Image(systemName: "play") } Text(item.name) Spacer() ProgressView() } } } struct ContentView: View { @State private var items = [ Item(name: "Item A"), Item(name: "Item B"), ] var body: some View { List { ForEach(items) { item in ItemRow(item: item) } } } } #Preview("Content view") { ContentView() } #Preview("Item row") { ItemRow(item: Item(name: "Item A")) } If I wrap the row in a container, like this: ForEach(items) { item in ZStack { ItemRow(item: item) } } the crash seems to disappear. Has anyone else seen this behavior? What might I be doing wrong? Any ideas about what could be causing this?

I have an iOS project based on SwiftUI in which almost all code is organised in Packages. With Xcode 26.2 and 26.3, I can preview all SwiftUI views without issues. With Xcode 26.4, the same previews don't work, in the canvas appears this error message: "Cannot preview in this file. Could not find target description for “TaskListView.swift”". The explanation is: "The list of source files that produce object files did not contain this file to be previewed. Check to make sure it is not excluded using the EXCLUDED_SOURCE_FILE_NAMES build setting." If I add a SwiftUI view to the main project files (not in a package), the preview works as expected. Is it an Xcode 26.4 regression? Or do I need to modify some configuration file?

Xcode tells me Previewing in executable targets now requires a new build layout for unoptimized builds. Either set ENABLE_DEBUG_DYLIB to YES for this target, or break out your preview code into a separate framework with its own scheme. How do enable that in Package.swift. swiftSettings don't work (.define and unsafeFlags with -D ...). Creating a library product that the executable then depends on doesn't help either. I have two targets, one is an executable target. The #Preview macro is in the non-executable target.

👋🏻 Hello Apple Developer Community, I’ve recently got the problem with the current Xcode Beta Version and the Preview Feature. Because when I try to load the Preview, the RAM Usage spikes and it’s nearly at the limit on my MacBook (16GB RAM). (Note: This is happening while loading up the Preview) But when I haven’t loaded the Preview Window, the overall RAM Usage of my system is ver low (Note: This is when Xcode has is not loading the Preview) (Note: This is after quitting Xcode for cancelling the load of the Preview) All Pictures are in German, sorry for that ☹️. What are possible problems or solutions against this problem? Have a nice day / evening 😁

Canvas Previews (targeting macOS) in both Xcode 16.4 & Xcode 26 fail to load, when the project imports a Swift package that imports and uses WebKit. I'm on macOS 15.5. Tried also to bring minimum targets of both the project and the package to 15.0. I see that there are some work-arounds for iOS simulator but nothing for the Mac. Anyone facing the same problem?

I'm trying out Xcode 12 (beta) and encountered an issue with TextField when viewing it in a live Preview. Although the view is interactive (scrolling vertically seems to be OK) and a cursor appears in the TextField view when it is clicked on, keyboard input is ignored. The same code works as expected in Xcode 11.5. Simulator in both 11.5 and 12 exhibits expected behaviour. Is this a bug? I know there is an issue with interactivity in Preview with multiple views inside PreviewProvider but I'd assumed this is if you'd added multiple Views to the same body of this struct.

Filed a feature request in feedback assistant, but starting a discussion here as well since I'm probably not the only one. The issue I have is that coding assistant and previews seem to be mutually exclusive. That means that when I'm iterating on UI, I either have to rely on the coding assistant showing me preview screenshots (cannot interact), firing up Device Hub (have to manually kick off a build after each change) or manually opening the associated preview (requires a lot of hoping back and forth). This feels inefficient and means I have to hop around and manage my windows and tabs more. A slight work around is to open a split view with the file and preview there. This layout is inefficient and clunky. I would love if Xcode supported a pinned preview next to coding assistant (or automatically showed the relevant one). I imagine this working just like showing a preview next to a file cmd + opt + return hides/shows the preview. FB23219611

I started a project targeting macOS and used Storyboard app lifecycle. I also used Xcode Previews in this project. If I: Keep the entry point of the main storyboard to a window controller. (as default setup in macOS), Turn the Xcode window into full-screen, That window controller would pop up its window every time Xcode Previews refreshes. I tested in Xcode 26.3 RC and many versions before.

Overview When a project contains SwiftData and the Preview uses a in memory database, SwiftUI preview doesn't show the data Have a look at the ContentView preview Environment Xcode 27.0 beta (27A5194q) 26.5.1 (25F80) Feedback FB23041713 Please can you have a look at the feedback, it also has a sample project and screenshot

I was playing around with the brand-new reorderable API and couldn't get it to work within previews. Is there a specific way to get previews to work with reorderable, or do I need to compile every time? I was also curious if there will be an addition to the Array generic struct, as it seems like the solution there currently is is just an extension, although the way it's being promoted makes it seem like it is built into the type.

I have this code As you can see, the locale of the Environment is different from the Locale given by .current. This is a problem for me because I have code that uses String(localized:) and AttributedString. I would like to be able to preview them with the locale I set in the Environment without any additional work on my part. I assumed these Apis would use the locale set by the environment but no, it uses the locale as decided by the schema used to build the preview app. The current solution I have is to manually change the App Language in the Preview's scheme to be whatever I need to correctly localize the language in Preview.

I have started to have issues with SwiftUI previews of iOS apps with projects under the Documents folder. I have experimented that in Xcode 26.4 and I am still seeing it in 26.5. The error is: Cannot preview in this file. Failed to launch xyz.abc.TestApp Looking at the diagnostics, Xcode gets a permission denied error when trying to open /Users/me/Documents/path/to/TestApp/DerivedData/TestApp/Build/Intermediates.noindex/TestApp.build/Debug-iphonesimulator/TestApp.build/Objects-normal/arm64/ContentView.1.preview-thunk-launch.o Error details below. Note that I have set DerivedData folders relative to the projects' roots. Additional information: I get errors on freshly created iOS projects, just trying to preview the default ContentView. Xcode has full disk access set in System Preferences > Privacy & Security. I have cleaned build folders, deleted the simulators, Xcode itself, cleared various caches, restarted and reinstalled Xcode to no avail. Checking Editor > Canvas > Use Legacy Previews Execution did not fix it either. Apps run fine in Simulator. System info: macOS 26.4.1, Xcode 26.5 (17F42), MacBook Pro M1 and Mac Studio M2 Max. I have found two ways to fix the problem while keeping DerivedData relative to the project's root: create the project in some other “unprotected” directory (/Users/me/Developer in my case), or uncheck Editor > Canvas > Automatically Refresh Canvas. Either way makes previews work again. Possibly related: SwiftUI preview not working in Xcode 26 when “Automatically Refresh Canvas” is enabled Xcode 13.2.1 - Simulator works, Preview doesn't Excerpt from diagnostics: | | [Remote] JITError | | | | ================================== | | | | | [Remote] CouldNotLoadInputObjectFile: Could not load object file during preview: /Users/me/Documents/TestApp/DerivedData/TestApp/Build/Intermediates.noindex/TestApp.build/Debug-iphonesimulator/TestApp.build/Objects-normal/arm64/ContentView.1.preview-thunk-launch.o | | | | | | path: /Users/me/Documents/TestApp/DerivedData/TestApp/Build/Intermediates.noindex/TestApp.build/Debug-iphonesimulator/TestApp.build/Objects-normal/arm64/ContentView.1.preview-thunk-launch.o | | | | | | ================================== | | | | | | | [Remote] XOJITError | | | | | | | | XOJITError: '/Users/me/Documents/TestApp/DerivedData/TestApp/Build/Intermediates.noindex/TestApp.build/Debug-iphonesimulator/TestApp.build/Objects-normal/arm64/ContentView.1.preview-thunk-launch.o': Operation not permitted

I am trying to preview my SwiftUI views but Xcode Preview Canvas failing. I tried everything that I found at internet but nothing works. Finally I created a new iOS project that contains only a view import SwiftUI struct ContentView: View { var body: some View { VStack { Image(systemName: "globe") .imageScale(.large) .foregroundStyle(.tint) Text("Hello, world!") } .padding() } } #Preview { ContentView() } Even this view cannot be previewed The error is Simulator was shutdown during an update Simulator [3E0DB935-C4C2-4566-BA48-8E21564C207C] failed to boot and may have crashed. I tried to restart xCode, restart Mac, download ios 26.0 sdk and created a simulator with that sdk but nothing helped. Do you have an idea?

In the first Xcode 16 beta, none of my SwiftUI previews work - they all just crash on start up. Has anybody run into this and found a workaround? Have tried all the usual steps of cleaning the project/restarting Xcode.

A foundation models bug I keep running into when in the preview phase of the testing. The error never seems to occur or break the app when I am testing on the simulator or on a device but sometimes I am running into this error when in a longer session while being in preview. The error breaks the preview and crashes it and the waring on it is labeled as : "Assert in LanguageModelFeedback.swift" This is something I keep running into, where I have been using foundation models for my project

Hi there, I just re-install 26.2, but I got many issues regarding to SwiftUI's components. How can I fix it? Do I need download or install something else?

Hello, I am facing a recurring issue with Xcode iOS simulator (preview). I want to preview a SwiftUI for iOS in Xcode, but the Simulator app fails to boot up. I receive the following error in Xcode: Cannot Preview in this file. Simulator was shutdown during an update. I have tried the following: Completely uninstalling XCode and deleting all developer data, then reinstalling everthing again. Shutdown and restart Deleting all developer data, deleting XCode cache Reinstalling iOS Simulator runtimes and reconfiguration of simulators. Tested using different simulator and runtime versions. "xcrun simctl --set previews delete al" My reported issues: FB20987522 FB20485454 Thank you Best regards, Jens

I'm running Xcode 26.2 (17C52). After deleting all simulators and creating new ones, SwiftUI Preview stopped working. Xcode reports: “Simulator [D774B214-XXXX-XXXX-XXXX-XXXXXXXX8288] failed to boot and may have crashed.” However, when I list all available simulators using xcrun simctl list, there is no simulator with that identifier. It seems Xcode is still referencing a previously deleted simulator. I have tried: Deleting all simulators again Creating new simulators Restarting Xcode and the system But the issue persists and Preview still fails to launch. Has anyone encountered this issue or knows how to clear the cached simulator reference used by SwiftUI Preview?

My main app target builds fine and can run on Simulator without issue. Whenever I try to run a Preview, I get this error: == DATE: Monday, November 3, 2025 at 2:52:23 PM Pacific Standard Time 2025-11-03T22:52:23Z == PREVIEW UPDATE ERROR: SimulatorShutdownUnexpectedlyError: Simulator was shutdown during an update Simulator [F85A5AF1-F52C-4662-AFCD-762F87AF537D] failed to boot and may have crashed. This seems like it started happening after updating to MacOS 26. I've tried reinstalling all Simulators, tried on Xcode 26, deleted derived data, restarted Xcode and my Mac several times. What other troubleshooting steps can I take?

I have a view inside a Swift Package that relies on an external Swift Package. My Preview Canvas breaks as soon as I use code from the external package: import ComplexModule // From swift-numerics import SwiftUI struct MyView: View { // Commenting out this line will make Previews work let number: Complex<Double> = 123 var body: some View { Text("Hello World") } } #Preview { MyView() } This is part of the error the preview emits: == PREVIEW UPDATE ERROR: GroupRecordingError Error encountered during update group #33 ================================== | [Remote] JITError: Runtime linking failure | | Additional Link Time Errors: | Symbols not found: [ _$sSd10RealModule0A0AAMc, _$s13ComplexModule0A0VMn, _$s13ComplexModule0A0V14integerLiteralACyxG07IntegerD4TypeQz_tcfC ] | | ================================== | | | [Remote] LLVMError | | | | LLVMError: LLVMError(description: "Failed to materialize symbols: { (static-MyTarget, { __replacement_tag$1 }) }") Did anyone else see this before?