Well looks like the problem is back, and the Allowed App option no longer actually allows it. Can't take game screenshots because of this Ransomeware garbage.
What has changed since this was resolved before ?
e.g. have you had an avast program update recently.
Whilst this is not resolving the problem directly:
There is nothing stopping you removing the Ransomware garbage (as you call it) module, but then your other images could be at risk.
Is Guild Wars 2 Screenshot folder on your C: drive and the same location as other images ?
I don't save any screenshots or images (or other at risk folders) in the windows default user locations. I also backup my images to an external hard drive (e.g. if you don't want to lose it back it up). Because of this I don't have the Ransomware component installed