Azure Pipelines "error MSB1009: Project file does not exist"

MSBuild was given a project or solution path that does not exist on the agent. The checkout layout or a wrong glob in the build task pointed it at a file that is not there.

What this error means

A VSBuild, MSBuild, or DotNetCoreCLI step fails with MSBUILD : error MSB1009: Project file does not exist. and the path it tried.

MSBUILD : error MSB1009: Project file does not exist.
Switch: src/App/App.csproj
##[error]The process 'C:\...\MSBuild.exe' failed with exit code 1

Common causes

Wrong path relative to the checkout root

The projects or solution input is relative to a different directory than where the repo checked out, so the file is not found.

A glob that matches nothing

A pattern like **/*.sln matches no file because the project lives in a sub-repo or was not produced by an earlier step.

How to fix it

Point at the project from the sources root

Use a path relative to the working directory and confirm it exists. $(Build.SourcesDirectory) anchors the checkout root.

- task: DotNetCoreCLI@2
  inputs:
    command: 'build'
    projects: '$(Build.SourcesDirectory)/src/App/App.csproj'

List files to confirm the path

1. Add a step that runs ls or dir at the expected directory.
2. Compare the real path to the one in the build task.
3. Fix the glob or path so it resolves to one real project or solution.

How to prevent it

• Anchor build paths to $(Build.SourcesDirectory).
• List the directory in CI when a path is uncertain.
• Verify globs match exactly one solution or project.

Related guides