当我尝试在 Xcode 的 Canvas 窗口中预览我的 SwiftUI 视图时，我的项目成功构建，但我在 Canvas 窗口中收到以下错误：

UVIntegration.DTXMessageError.messageRepliedWithError("Connecting to
launched interactive agent 6310", Optional(Error
Domain=com.apple.dt.ultraviolet.service Code=17"connectToPreviewHost:
Failed to connect to 6310: Error Domain=RemoteBundleLoaderError
Code=17"Failed to load library
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/Library/PrivateFrameworks/XCPreviewKit.framework/Versions/Current/XCPreviewKit
due to missing bootstrapping symbols"
UserInfo={NSLocalizedDescription=Failed to load library
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/Library/PrivateFrameworks/XCPreviewKit.framework/Versions/Current/XCPreviewKit
due to missing bootstrapping symbols}"
UserInfo={NSLocalizedDescription=connectToPreviewHost: Failed to
connect to 6310: Error Domain=RemoteBundleLoaderError Code=17"Failed
to load library
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/Library/PrivateFrameworks/XCPreviewKit.framework/Versions/Current/XCPreviewKit
due to missing bootstrapping symbols"
UserInfo={NSLocalizedDescription=Failed to load library
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/Library/PrivateFrameworks/XCPreviewKit.framework/Versions/Current/XCPreviewKit
due to missing bootstrapping symbols}})))

GenericHumanReadableError: unexpected error occurred
messageRepliedWithError("Connecting to launched interactive agent
6310", Optional(Error Domain=com.apple.dt.xcodepreviews.service
Code=17"connectToPreviewHost: Failed to connect to 6310: Error
Domain=RemoteBundleLoaderError Code=17"Failed to load library
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/Library/PrivateFrameworks/XCPreviewKit.framework/Versions/Current/XCPreviewKit
due to missing bootstrapping symbols"
UserInfo={NSLocalizedDescription=Failed to load library
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/Library/PrivateFrameworks/XCPreviewKit.framework/Versions/Current/XCPreviewKit
due to missing bootstrapping symbols}"
UserInfo={NSLocalizedDescription=connectToPreviewHost: Failed to
connect to 6310: Error Domain=RemoteBundleLoaderError Code=17"Failed
to load library
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/Library/PrivateFrameworks/XCPreviewKit.framework/Versions/Current/XCPreviewKit
due to missing bootstrapping symbols"
UserInfo={NSLocalizedDescription=Failed to load library
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/Library/PrivateFrameworks/XCPreviewKit.framework/Versions/Current/XCPreviewKit
due to missing bootstrapping symbols}}))

清理构建文件夹，然后杀死 Xcode，启动 Xcode，进行完整构建可能(有时)会解决问题。然后整个马戏团又开始了。
我认为这对苹果来说有点可惜。最令人沮丧(至少对我而言)是文档几乎不存在。这都是反复试验。主要是错误。

我已经两次遇到这个问题了。我没有一个简单的解决方案，但只有在 macOS Catalina 有可用的软件更新时才会发生。例如，我现在使用的是 10.15.5，但有 10.15.6 的更新，我遇到了这个问题。

希望对您有所帮助，而且错误不只是说"更新您的 macOS"或其他内容，这真的很烦人。