When using the Publish Build Artifacts task, the following error gets thrown in the build (just after "Get sources"):
The definition for the task does not have a handler that matches any supported by this agent. Supported handlers: AzurePowerShell, AzurePowerShellHandler, PowerShell, PowerShellHandler, PowerShellExe, PowerShellExeHandler, Process, ProcessHandler
I am using the VSTS (formally known as VSO) Host Agent.
I can reproduce this issue too. Checked the source code for "Publish build artifacts", this issue seems to be caused by the PowerShell script is missing. I have help you submit a feedback to MS, you can track the status here.
For now, you can use "Copy and Publish Build Artifacts" task to publish your artifacts.
来源：https://stackoverflow.com/questions/33917308/vso-vsts-error-when-using-publish-build-artifacts-on-the-host-agent