Xbox 360 memory unit

It's model 1439 and under storage devices it says memory unit with a black pic of the Xbox 360 then memory unit with a black USB stick and then the cloud.

Often in the older 360 consoles with the built in memory unit, this issue will occur.

When the memory unit fails, the Xbox sees that there's an update available since it can't see the update that was on the storage device. When the Xbox tries to download/install the update, the update can't install because of the failed storage device.

Does your Xbox 360 have the memory unit and/or the hard drive?

When the memory units fail in those Xbox 360 consoles, you can't delete or install anything and you'll often get prompted to install a system update which won't install either.

If you can try and exchange the 360 with gamestop that would be best and get a 360 without a memory unit. The systems without a memory unit will require an internal hard drive.

Description of the limits on Xbox 360 Gamer profile names



Up to eight profiles can be stored on each USB Memory Unit (the 4GB 360 S contains an internal, nonremovable 4GB USB Memory Unit)

Up to 32 profiles can be stored on each XBOX 360 HDD



To store more profiles, add another USB Memory Unit or HDD.

This could be a glitch since you have mentioned that there is nothing in the memory unit which is why a reset could help resolve the issue. Please follow the steps mentioned here => How to reset or reformat your Xbox 360 to factory default settings | Xbox Support.