Azure Web App deploy: Web Deploy cannot modify the file on the destination because it is locked by an external process

Dave New picture Dave New · Jun 20, 2016 · Viewed 16.4k times · Source

I am using the "Azure Web App Deployment" build step in VSTS to publish an ASP.NET Core API to an Azure Web App:

Azure Web App Deployment

Occasionally, this step breaks with the following error:

[error]Microsoft.Web.Deployment.DeploymentDetailedClientServerException: Web Deploy cannot modify the file 'MyProject.Api.exe' on the destination because it is locked by an external process. In order to allow the publish operation to succeed, you may need to either restart your application to release the lock, or use the AppOffline rule handler for .Net applications on your next publish attempt. Learn more at: http://go.microsoft.com/fwlink/?LinkId=221672#ERROR_FILE_IN_USE.

This GitHub issue raises the same issue, but there is no suggested solution using the Azure Web App Deployment build step.

Answer

Ben Barreth picture Ben Barreth · Dec 15, 2016

As per a separate thread in the Microsoft Github repo here, there's a hacky workaround where if you add the following key to the Azure Appsettings, it can help resolve the locked file deployment error:

MSDEPLOY_RENAME_LOCKED_FILES = 1

I'm not sure how long this appsetting hack will be supported, but it did help solve the issue for me personally.

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