今天早上 上班发现钥匙串中的全部证书 都 提示此证书签发者无效

Thanks for bringing this to the attention of the community and apologies for the issues you’ve been having. This issue stems from having a copy of the expired WWDR Intermediate certificate in both your System and Login keychains. To resolve the issue, you should first download and install the new WWDR intermediate certificate (by double-clicking on the file). Next, in the Keychain Access application, select the System keychain. Make sure to select “Show Expired Certificates” in the View menu and then delete the expired version of the Apple Worldwide Developer Relations Certificate Authority Intermediate certificate (expired on February 14, 2016). Your certificates should now appear as valid in Keychain Access and be available to Xcode for submissions to the App Store.

系统证书WWDR在2016年2月14日失效，须要更新WWDR系统证书。

解决的方法

1.下载证书，地址https://developer.apple.com/certificationauthority/AppleWWDRCA.cer 

2.双击下载的证书。

3.在钥匙串里面的登录 删除 Apple Worldwide Developer Relations Certification Authority 证书

4.在钥匙串里面的系统 删除 Apple Worldwide Developer Relations Certification Authority 证书

ps：假设这里找不到Apple Worldwide Developer Relations Certification Authority 证书。点击显示-->显示已过期的证书。

5.找到開始下载的Apple Worldwide Developer Relations Certification Authority 证书，双击。

ok  问题解决。