When you upgrade an enrolled Windows RT-based device to Windows 8.1 RT General Availability, all modern apps that were installed through the Company Portal app before the upgrade may not function immediately, and an "X" may be displayed on the apps tile.
Even though you can open the Company Portal app, you cannot use the apps that were installed from the Company Portal app until the device is connected to the Microsoft Intune service. After the device is connected, the Windows "side-loading" keys are re-provisioned, and the functionality of the apps is restored.
To work around this problem, take one of the following actions:
- Open the Company Portal app, and then click to install any of the available modern apps.
- Open an administrative command prompt on the Windows 8.1 RT General Availability-based device, type the following command, and then press Enter:MDMAgent.exe