在Win 7的环境变量中改变PATH变量后，有相同的变量。更改回默认值有帮助。

当我的后构建事件脚本试图运行指定路径中不存在的批处理文件时，我有错误9009。

Tfa的回答被否决了，但实际上会导致这个问题。 多亏了hanzolo，我在输出窗口中找到了以下内容:

3>'gulp' is not recognized as an internal or external command,
3>operable program or batch file.
3>D:\dev\<filepath>\Web.csproj(4,5): error MSB3073: The command "gulp clean" exited with code 9009.

在运行npm install -g gulp后，我不再得到这个错误。如果在Visual Studio中出现此错误，请检查输出窗口并查看问题是否是未设置的环境变量。

检查拼写。我试图调用一个可执行文件，但有名称拼写错误，它给了我退出与代码9009消息。

很可能在最终路径上有空间。

您可以通过引用路径来解决这个问题，从而允许使用空格。例如:

xcopy "$(SolutionDir)\Folder Name\File To Copy.ext" "$(TargetDir)" /R /Y /I

Yet another reason: If your pre-build event references another projects bin path and you see this error when running msbuild, but not Visual Studio, then you have to manually arrange the projects in the *.sln file (with a text editor) so that the project you are targeting in the event is built before the event's project. In other words, msbuild uses the order that projects are listed in the *.sln file whereas VS uses knowledge of project dependencies. I had this happen when a tool that creates a database to be included in a wixproj was listed after the wixproj.