Explanation
The most likely issue that prevents the user's mobile device from saving pictures to an external drive at home is that the peripherals are managed via MDM (mobile device management). MDM is a software solution that allows an organization to remotely control, secure, and enforce policies on mobile devices, such as smartphones, tablets, or laptops. MDM can also restrict the access and functionality of the peripherals, such as external drives, cameras, microphones, or printers, that are connected to the mobile devices.
One of the possible reasons why the user's mobile device can back up classified files to an external hard drive at work but not save pictures to an external drive at home is that the MDM policy allows only authorized peripherals to be used with the mobile device. For example, the MDM policy may require the external drive to have a certain encryption level, a specific serial number, or a valid certificate to be recognized by the mobile device. The external drive at work may meet these criteria, while the external drive at home may not.
Therefore, the mobile device can back up the classified files to the external drive at work, but it cannot save the pictures to the external drive at home.
To resolve this issue, the user may need to contact the IT administrator or the MDM provider and request permission to use the external drive at home. Alternatively, the user may need to use a different method to transfer the pictures from the mobile device to the external drive, such as using a cloud service, a wireless network, or a USB cable.
References:
What is Mobile Device Management (MDM)?1
How to Manage Mobile Devices With MDM2
How to Connect an External Hard Drive to Your Phone3

A sandbox is a virtual environment that isolates the engineer's research activities from the rest of the system. This allows the engineer to test, experiment, and modify the system without affecting the real data, applications, or settings. A sandbox is the best environment for research purposes because it provides a safe and controlled way to explore new ideas, simulate scenarios, and troubleshoot problems. A sandbox can also be easily reset or deleted after the research is done.
Reference
What is a Sandbox Environment?
Chapter 4: Virtualization and Cloud Computing

Explanation
Lightning is a proprietary connection type that is used by Apple devices, such as iPhones, iPads, and iPods, to transfer data, charge, and connect to accessories. Lightning cables have a reversible 8-pin connector that can be plugged into a USB port on a workstation or a power adapter. USB-C, serial, and NFC are not compatible with Apple phones.
Reference: [CompTIA A+ Core 1 (220-1101) Certification Study Guide], page 13.

Explanation
Before attempting to resolve the issue, it is important to first determine the cause or probable cause of the issue, so that a plan of action can be developed. In this case, the fact that the retention policy was updated shortly before users first noticed the issue suggests that this could be the cause of the issue. The systems administrator should investigate this further to determine if this is indeed the cause of the email server issue.

To connect a mobile phone to a car, you need to pair them using Bluetooth, which is a wireless technology that allows secure local networks between devices1. If one phone can connect to the car but another cannot, it means that the first phone has Bluetooth enabled and paired with the car, while the second phone does not. Therefore, the user should check the Bluetooth settings on the second phone and make sure it is turned on and discoverable21.