in fact, to be more specific, it's the ransomware engine that "protects" (read blocks) all kinds of files, folders and tons of file-extensions ... found 2 solutions here :

1. deselecting all extentions (png jpeg...) in the "picture" list of antiransomware protectionsettings (made FS work properly) and deselecting database and design file extensions made airlibrary work or
2. whitelist every program LSMGUI.exe, poserpro.exe, FSviewer.exe in the RANSOMWARE whitelist, and not the firewall whitelist as i said earlier.

conclusion : iobit tightened the securityknot a bit as standard settings. downside : took a lot of digging and try-and-error before finding the cause. iobit is not very transparent on accessing securitysettings imo.

Anyway, just letting you all know in case someone comes accross similar probs with airlibrary or such :)