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It is not possible to deploy an application to a specific Windows machine when the user has logged in to multiple machines with the same user account. When deploying an application to a user collection with the option "An administrator must approve a request for this application on the device", the application will be available on all machines where the user has logged in. Similarly, when deploying the application to a device collection with the same option, the application will not appear in Software Center until it is approved and deployed to that specific device.
One possible workaround is to create a separate user account for the user on the second Windows machine and deploy the application to a user collection with the option "An administrator must approve a request for this application on the device". This way, the application will only be available on the machine where the user is logged in with the designated user account.
Another option is to use the client setting "Hide unapproved applications in Software Center" to hide the application from Software Center on the second Windows machine. This way, the application will still be available for installation on both machines, but will only be visible in Software Center on the first machine.
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