当我将我的自定义框架添加到项目中时，在我更新Xcode后，我遇到了同样的问题。

解决方案:在项目的构建设置下搜索验证工作区 更改为yes，默认设置为no

No doubt that the fix in case of Xcode 12.3 is to setup the Validate Workspace property in the target's build setting. However if you check the diff after this change, the reason of the build error is the missing parameter (VALIDATE_WORKSPACE) from the project file, not the value of the parameter. So you don't need the value to be YES. You need to add the value to the project settings and you can leave it on the default value (NO). At the first time, it shows up in the Build Settings with NO, but only because that is the default value of the missing parameter.

TLDR; 在不更改项目设置的情况下，转到目标的构建设置，找到“验证工作区”，将其设置为YES，然后设置回NO。

Xcode 12.3

在我的案例中，我通过在Build Settings选项卡中简单地将Validate Workspace设置为Yes来解决这个问题

如果使用Carthage，请确保使用copy-frameworks脚本，而不是使用Embed & Sign作为嵌入内容。我得到了同样的错误，因为我忘记了。

可能的原因是

framework which you are using may not be built for simulator architecture(x86_64), you can check the compatibility by going to framework folder (framework_name.framework --> modules --->framework_name.swiiftModule-->) in this path you should see arm/i386/x86_64 support files if you have updated to new Xcode, the frameworks you are using are not compatible to the newer compiler version, so vendor needs to share the recent compatible one, in this case you will not be able to run on both device and simulator

如果你是Xcode的新手，使用Xcode只是为了启动模拟器来运行appium工具，以上步骤可能会比较复杂。对于初学者来说，使用小于11的xcode版本即可。

此链接有助于下载xcode 10.3

Xcode10.3

如果你尝试从AppStore下载，我们需要有高达40gb的空闲存储空间，上述' xip文件将不会导致存储错误。

你可以稍后感谢我，如果这工作!!