Hi, @Taylor Crowley
Thank you for posting in Microsoft Q&A forum.
The issue you are facing with MDT image deployment failing to deploy applications with a '1603' MSI error message on a brand new machine could be due to the fact that the local admin account is not enabled or the password is not set correctly.
The deployment gets stuck on the sign-in page trying to access the local admin account '.\Administrator because the account is not enabled or the password is incorrect.
When you try to deploy again to the same machine, it uses your domain local admin which is pushed to all machines via GPO. This time it installs all apps with no problem because the domain local admin account is used instead of the local admin account.
To resolve this issue, you can try enabling the local admin account and setting the password correctly before deploying the image to a new machine. Alternatively, you can create a new local admin account with a different name and password and use that account for the deployment.
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