No, it's not technical at all (technical is to ask you to put 3598 to MTP mode, then make system protected and hidden files and folders visible, then asking you for screenshots of almost everything on 3598, file names, sizes and time stamps, just to see what GE has done to your device, and if you use a MAC, god help us!!!!!);)
So there is no CN Europe NTU 2016.30 in your myMaps list.
Backup your microSD and format it and then start a new update using Garmin Express (Device and Computer download).
If everything goes OK with Garmin Express, unplug your 3598, preform a Clear Nonvol and you should be OK.
The total size of the update should be around 12 Gb, ~4.8 for PC version, plus all the files needed for the 3598, that are first downloaded and copied on the PC and then copied on the 3598 (internal memory or card, it's GE decision which file is written where).