创建一个新用户帐户，切换到帐户，打开XCode并尝试运行项目。在尝试了所有其他建议都没有成功之后，我不仅再次能够在sim上运行，而且原来的帐户现在也可以工作了。

I was having this very annoying issue since a long time too. I've 3 different XCode versions installed and I'm not sure whether it's the reason or not that none of the above solutions worked for me. But here is the solution I finally found: I don't kill the running Simulator, I just try to launch it again using a Spotlight search, enter "Simu" and you should find it in Applications, then hit Enter. As it's yet running it will magically start my app that was frozen/locked/waiting for attachment. It works perfectly for me now and I hope it will also work for some (all?) of you.

顺便说一句，我用Cmd+空格来调用Spotlight，这样就可以非常快速地解冻模拟器而不使用鼠标。

我什么都试过了。我的“包装器扩展”是空的，应用程序没有安装在模拟器。我把“包装器扩展”改为“应用程序”，现在它安装在模拟器中。

它仍然挂在附加到APP_NAME…

编辑 升级到Xcode 4.3，几次重新启动和清洁&构建，现在工作....

我有这个问题，但问题不同。

另一个应用程序正在尝试向密钥链添加证书，并且由于某种原因(网络?)而挂起。重复这几次，只有当钥匙链是免费的，xcode才能运行应用程序。

固定它! !希望这能帮助一些人避免非常沮丧的几个小时。我用以下方法解决了这个问题:

Clicking on the project name in the left pane (at the very top). This will bring up a new menu to the right, something like the project/ target editors in XCode 3. Click on Build Settings up at the top. Under Packaging make sure your product name is the same for every build, and equal to whatever it says it's attaching to. Eg if XCode is Hanging at "Attaching to myLCBO" but your product name is "LCBO Finder" then it won't build. That was exactly my problem because I renamed my app half way through development.

在这个问题上，我试了所有主要的方法，但还是不管用。然后我进入目标信息(在项目设置部分)。在“自定义iOS目标属性”中，旧的产品名称出现在:

可执行文件 Bundle显示名称 包的名字

我不得不改变这些，以配合我的产品名称。然后我重置了模拟器，它工作了。