Following the KB5121003 Patch Tuesday update, users on ARM64 devices like Surface Laptop 7 and Surface Pro 11 are facing startup failures with Microsoft Teams and New Outlook, while traditional Win32 applications remain unaffected. Reverting to the previous update restores functionality, but recovery options have not resolved the issue. The root cause appears to be broken AppModel Runtime package states, leading to dependency issues and 0x80073CFC errors. This problem is similar to one caused by update KB5094126 earlier this year. Creating new Windows profiles offers only temporary relief, and administrators are advised to pause the deployment of KB5121003 on ARM devices until the issue is addressed.