修復 Xcode 錯誤 “The identity used to sign the executable is no longer valid”

如圖：

解決方法來自：http://stackoverflow.com/questions/7088441/the-identity-used-to-sign-the-executable-is-no-longer-valid/14275197

Restarting Xcode didn't work for me. What fixed it for me was going to Accounts in Xcode (in preferences), Details for my developer account then clicking the refresh icon at lower left. That loaded a new team provisioning profile, which apparently was needed... yeah. We shouldn't have to deal with this Apple. Microsoft used to do this stuff to developers, don't go there.?–??Eskim0?Mar 9 at 3:34

步驟：

1. 打開Xcode配置（Xcode -> Preferences...）
2. 選擇Accounts頁面，選中你的Apple ID，點右下方的「View Detail...」按鈕
3. 點擊左下角的刷新按鈕，等待刷新完成，點「Done」按鈕，關閉Xcode配置窗口
4. 重新編譯運行項目，若出現修復窗口，一路點「Fix Issue」按鈕

還有其他解決辦法，見引用上面的鏈接。