Hey there, let's break down this confusing issue you're hitting. First off, that error code 4294967295 translates to 0xFFFFFFFF—a generic unhandled Win32 error, which explains why you're seeing that conflicting "username or password incorrect" message instead of a clear root cause. The lock folder association is still a strong lead here, so let's walk through actionable fixes:

Possible Fixes to Try #

• Verify Deployment Credentials First
  Even though the message might be misleading, it's worth ruling out actual credential issues. Grab the publish profile from your Azure Function App (Portal > Function App > Overview > Get publish profile) and cross-check the username/password against what's configured in your VSTS service connection or deployment task. You can also test a manual deployment using msdeploy.exe with those credentials to confirm they work.

• Eliminate File Lock Conflicts
  Since the error code points to folder locks, try these steps to bypass in-use files:

  • Add stop/start tasks in your VSTS pipeline: Insert an Azure App Service Manage task before deployment to stop the app, then another one after deployment to start it back up. This ensures no processes are holding onto files during deployment.
  • Enable App Offline mode: Modify your VSTS deployment task to include the argument -enableRule:AppOffline. This creates an app_offline.htm file during deployment, which takes the app offline temporarily and releases file locks.

• Check Web Deploy Configuration

  • Ensure the VSTS agent has the latest version of Web Deploy (MSDeploy V3 or newer) installed. Outdated versions can cause unexpected permission or lock issues.
  • Confirm the Web Deploy extension is enabled on your Azure Function App (Portal > Function App > Deployment Center > Settings). If it's missing, reinstall it.

• Dig Into Detailed Logs
  Enable verbose logging in your VSTS deployment task (under "Additional Deployment Options") to get more granular error details. You can also check the Log Stream in your Azure Function App portal to see real-time server-side logs that might reveal exactly which file/folder is locked or where permission is failing.

Error Log Reference #

2018-01-28T08:31:58.6556754Z ##[error]Failed to deploy web package to App Service.
2018-01-28T08:31:58.6568081Z ##[error]Error: (1/28/2018 8:31:58 AM) An error occurred when the request was processed on the remote computer. Error: The user name or password is incorrect. at Microsoft.Web.Deployment.NativeMethods.RaiseIOExceptionFromErrorCode(Win32ErrorCode errorCode, String maybeFullPath) at Microsoft.Web.Deployment.DirectoryEx.CreateDirectory(String path) at Microsoft.Web.Deployment.DirectoryEx.CreateDirectoriesFromRoot(String path) at Microsoft.Web.Deployment.AppOfflineRuleHandler.AddAppOfflineFilesToEachApp(DeploymentBaseContext baseContext, Boolean whatIf) at Microsoft.Web.Deployment.AppOfflineRuleHandler.Add(DeploymentSyncContext syncContext, DeploymentObject destinationObject, DeploymentObject& sourceObject, Boolean& proceed) at Microsoft.Web.Deployment.DeploymentSyncContext.HandleAdd(DeploymentObject destObject, DeploymentObject sourceObject) at Microsoft.Web.Deployment.DeploymentSyncContext.SyncChildren(DeploymentObject dest, DeploymentObject source) at Microsoft.Web.Deployment.DeploymentSyncContext.SyncChildrenNoOrder(DeploymentObject dest, DeploymentObject source) at Microsoft.Web.Deployment.DeploymentSyncContext.SyncChildren(DeploymentObject dest, DeploymentObject source) at Microsoft.Web.Deployment.DeploymentSyncContext.SyncChildrenOrder(DeploymentObject dest, DeploymentObject source) at Microsoft.Web.Deployment.DeploymentSyncContext.SyncChildren(DeploymentObject dest, DeploymentObject source) at Microsoft.Web.Deployment.DeploymentSyncContext.ProcessSync(DeploymentObject destinationObject, DeploymentObject sourceObject) at Microsoft.Web.Deployment.DeploymentObject.SyncToInternal(DeploymentObject destObject, DeploymentSyncOptions syncOptions, PayloadTable payloadTable, ContentRootTable contentRootTable, Nullable1 syncPassId, String syncSessionId) at Microsoft.Web.Deployment.DeploymentAgent.HandleSync(DeploymentAgentAsyncData asyncData, Nullable1 passId, String user, String siteName) Error count: 1.
2018-01-28T08:31:58.6575553Z ##[error]Error: C:\Program Files\IIS\Microsoft Web Deploy V3\msdeploy.exe failed with return code: 4294967295

内容的提问来源于stack exchange，提问作者Federico Degrandis