As stated, providing advice on how to break the standalone media encryption would be pretty unfair to artists and scripters who want to retain control of their work, and still allow users to incorporate them into games. It will have to remain a secret for the benefit of all. It is, however, a powerful game developers life lesson (and the first of many I am sure) that everyone should take back-ups seriously. I myself have GitHub, which it's common for me to check in several times during a coding day, then I have a daily SSD backup which snapshots the whole drive to an identical one, and then I have a file backup which scans for changes and backs that up on a larger HDD at the end of the day, and finally I have a monster back-up which happens every week or so and goes to a NAS system for long term storage. It's not that I like having lots of storage (as it's pretty much a nightmare lugging around 80% redundant files) it's just what I learned from losing everything from a line of complicated code to an entire month worth of game engine work. If there is anything good from losing your assets, is that when you create them again, they will usually be better
The 'Kaspersky ' issue is what is called a False Positive, which you can report to them and they will create a whitelist entry in their next update to allow GameGuru through, or you can exclude the GameGuru folder from your scan as a short-term measure. I personally use ESET as it's super fast and has 'never' mistook any of my tools and applications as viruses.
PC SPECS: Windows 8.1 Pro 64-bit, Intel Core i7-5930K (PASSMARK:13645), NVIDIA Geforce GTX 980 GPU (PASSMARK:9762) , 32GB RAM