Xcode · Swift · iOS · macOS
Fix Xcode errors, Swift bugs & iOS problems, fast.
Step-by-step fixes for build errors, code signing, SwiftUI, App Store Connect and the bugs that come with every new iOS and macOS release.
Browse by topic
For developers
Xcode Errors
Build failures, code signing and provisioning, simulator problems, archive and upload errors.
For developers
Swift & SwiftUI
Swift and SwiftUI explained with working code: concurrency, data flow, navigation, compiler errors.
For developers
App Store & TestFlight
App Store Connect, TestFlight builds, App Review rejections and StoreKit issues.
For iPhone & iPad
iOS Fixes
Battery drain, Wi-Fi, Bluetooth, storage and app problems after iOS updates.
For Mac
macOS Fixes
macOS update problems, Finder, external drives, storage and apps that won’t open.
What’s new
Developer Updates
New Xcode, SDK and OS releases: what changed, known issues and what to update.
Latest guides
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Fix: Mach-O Linker Error ‘No such file or directory’ for .a on Device
Why Xcode’s linker can’t find your static library .a file when building for a device, and how to fix architecture and dependency…
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Fix: Liquid Glass Sheet Color Mismatch Between Views and .borderedProminent Buttons in SwiftUI
Learn why system colors render differently in Liquid Glass sheets and how to make filled views match .borderedProminent button tints on iOS…
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How to Round a Double to X Decimal Places in Swift
Round a Swift Double to any number of decimal places with a small extension, and learn when to use String(format:), NumberFormatter or…
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Why FCM Topic Notifications Aren’t Saved to Hive on iOS
FCM topic pushes show on the iOS lock screen but never reach your Hive history. Here’s why iOS skips your background handler,…
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Fix: ‘No connected devices’ When Flutter Won’t See the iOS Simulator
flutter run says No connected devices on macOS? Boot a simulator, point xcode-select at Xcode, install a runtime, and target the device…
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![Fix: Array Extension Requires ‘[T]’ and ‘[any TextContainer]’ Match](https://apple-developers-inc.com/wp-content/uploads/2026/10/fix-array-extension-requires-t-and-any-textcontainer-match.jpg "Fix: Array Extension Requires '[T]' and '[any TextContainer]' Match")
Fix: Array Extension Requires ‘[T]’ and ‘[any TextContainer]’ Match
Why a generic T: TextContainer won’t satisfy an Array extension written for [any TextContainer], and how to rewrite the extension so both…
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Fix: Instance member ‘someVar’ cannot be used on type ‘InnerView’
SwiftUI nested structs can’t read the parent view’s properties. Use computed properties, parameter passing, @Binding or @Observable to share state cleanly.
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Fix: Undefined symbols for architecture arm64 in Xcode
Solve the Xcode linker error Undefined symbols for architecture arm64 by restoring $(inherited) linker flags, checking the library’s arm64 slice, and reinstalling…
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How to Do Sample-Accurate AVPlayer Audio Scrubbing in Reverse
AVPlayer can’t render sample-accurate or reversed audio while scrubbing. Here’s why, and how to drive PCM playback through AVAudioEngine yourself.
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Fix: Unexpectedly found nil while unwrapping an Optional value
Why Swift crashes with ‘Unexpectedly found nil while unwrapping an Optional value’, how to find the line, and fix it with if…
Built from real problems
Every guide starts from an actual error message, release note or issue developers and users are hitting right now.
Fix first, theory second
A quick answer at the top, then the fixes in order of what’s most likely to work, with code you can copy.
Sources you can check
We link Apple’s release notes and the original discussions, and update guides when new versions change the answer.