https://github.com/Microsoft/vsts-extension-build-release-tasks/blob/7e4486c4681e45412a06cd2859c1f65fa85ad737/BuildTasks/Common/Common.ts#L519 There are two issues: 1. If the contribution in the vss-extension.json does not end in a forward slash it does not search the correct directory. 2. The directory being searched is incorrect as **taskRoot** is joined in the path twice.