我也遇到了同样的问题:我第一次是在跑步时把证书下载到我的小MacBook上的。当我试图在iMac上安装证书时…然后我遇到了这一页上描述的问题。

和你们很多人一样，我花了几个小时把头发揪出来，然后我按照下面的步骤来解决它:

Close all your stuff except your webpage that should be logged into App Dev center. Open Xcode. Click WINDOW > ORGANIZER. Then click the Devices tab and select "Provisioning Profiles" on the left. That should bring up your provisioning profiles. Highlight one by one (if more than 1), right click and delete profile. Yes, just do it! Delete them all! (I kept making a new one after a new one trying to make the thing work.) From the first page you see after logging into the App Dev Center on the right side click "iOS PROVISIONING PORTAL" > (do not "launch assistant"). Instead click on the left side. Select CERTIFICATES. You will probably have just one line listed with your name/company - from there click on the right side REVOKE. Click OK to verify that's what you want to do. On the same page click DEVICES. Click the box next to your device you are trying to provision and click REMOVE SELECTED. Again click OK to verify. Wait about 2 minutes to let Apple do their thing. Now click on "HOME" that is on the left side navigation. Click "Launch Assistant" create a new app ID - call it whatever you want. Just make sure it's unique enough to know that's the one you just created because the others you've been messing with all day will not be deleted from Apples Dev Center. You should be able to follow the rest of the Assistant without troubles -- the main thing is you just had to delete your old provision profiles and start over.

好运！

对我来说，只有当证书和两个密钥都在Login keychain中时，它才有效。我之前创建了一个开发钥匙链，但是Xcode管理器在那里找不到钥匙。所以我把它们移回登录，退出钥匙链工具-瞧，Xcode管理器中的错误消失了!这是在3.1.3 SDK的雪豹10.6.2上。

如果你有新的mac，你可以去 IOS开发中心->供应门户->证书->开发->撤销并创建新证书。我的问题解决了。我的错误是“代码签名错误:身份'iPhone开发人员'不匹配任何有效的，未过期的证书/私钥对在您的钥匙串”

我得到的最佳答案是导出您的密钥，而不是仅仅试图导入证书文件。

当您从生成请求的密钥链中导出密钥时，您将得到一个Certificates。P12文件，将需要的键滚动在一起。

然后将其导入新计算机。

对于这样的密钥，最好保留一个滚动的证书包文件，因为很多时候“公共”密钥或证书文件不足以进行恢复。

Because I keep coming back to this question, I will leave my answer here for the solution that works for me. It turns out that for a same public/private key developer identifier of me, it's installed twice in my keychain. Both have private key. But when I compare, one is private key of me within my developer organisation, and another one is private key of me as a personal developer. It turns out Xcode keeps trying using the wrong key. Removing the wrong duplicate key solves all the problem. Hey future me, check this one first next time!

我发现我需要拖动distribution_identity。我从开发人员程序门户网站上的“Certificates -> Distribution”页面下载的cer文件到密钥链访问程序中，然后这个错误就消失了。