WatchKit apps must have a deployment target equal to iOS 8.2 (was 8.3)?

Select your project settings and go to "TARGETS". Click on your Watch Kit App, select Build Settings. For the key "iOS Deployment Target" you should find "iOS 8.3". For some reason Xcode 6.3 Beta 4 wants to have this on "iOS 8.2" for "Debug" and "Release". Now your project should build as expected.

This is still true for XCODE 6.3 release!

Target -> "appName" Watch Kit App -> search Deployment -> change iOS Deployment Target on iOS 8.2 -> run

Ran into this myself. Seems like a bug in Xcode 6.3 beta 4.

I analyzed the project.pbxproj file (in text view) of a freshly created project with a WatchKit extension. It looks like there is a setting:

IPHONEOS_DEPLOYMENT_TARGET = 8.2;

...which is missing from our projects created with earlier Xcode versions.

So I manually copied this setting into the Debug and Release configurations of my project. This error went away.

I then got another error about a version mismatch between my app and the WatchKit app target. Fixing this version mismatch allowed the build to compile clean and run fine.

I know this is a bit hacky, but I'm guessing it's relatively safe.

When searching through the project.pbxproj file, you will want to match against this search term: "_WatchKit_Extension". This should identify the area near where the new instruction should be added.

Discussion thread in Apple forums:

https://devforums.apple.com/thread/266033?tstart=0

Excerpt from a fresh project:

4F9F32751AC2024F00673D86 /* Debug */ = {            isa = XCBuildConfiguration;            buildSettings = {                ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;                GCC_PREPROCESSOR_DEFINITIONS = (                    "DEBUG=1",                    "$(inherited)",                );                IBSC_MODULE = Bogus_WatchKit_Extension;                INFOPLIST_FILE = "Bogus WatchKit App/Info.plist";                IPHONEOS_DEPLOYMENT_TARGET = 8.2;                PRODUCT_NAME = "$(TARGET_NAME)";                SKIP_INSTALL = YES;                TARGETED_DEVICE_FAMILY = 4;                "TARGETED_DEVICE_FAMILY[sdk=iphonesimulator*]" = "1,4";            };            name = Debug;        };        4F9F32761AC2024F00673D86 /* Release */ = {            isa = XCBuildConfiguration;            buildSettings = {                ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;                IBSC_MODULE = Bogus_WatchKit_Extension;                INFOPLIST_FILE = "Bogus WatchKit App/Info.plist";                IPHONEOS_DEPLOYMENT_TARGET = 8.2;                PRODUCT_NAME = "$(TARGET_NAME)";                SKIP_INSTALL = YES;                TARGETED_DEVICE_FAMILY = 4;                "TARGETED_DEVICE_FAMILY[sdk=iphonesimulator*]" = "1,4";            };            name = Release;        };