A bug in Exclusions ?

I try to add an Exclusions, e.g. \\a\b, when I press OK to save it, then the Windows OS hang several minutes. Is it a bug?

NOD32 version is 3.0.672.

 

If I put in a UNC directory that I either can't resolve because I typed it wrong or the name isn't in DNS, WINS, or reachable via NetBIOS broadcasts or because the credentials that egui.exe is running with do not have permissions to access the share you will hit the issue that Windows always has when it very ungracefully tried to connect to a network resource and takes upwards of a minute for it to fail. This seems to be more of an issue with the way Windows handles networking and its API calls than anything else, though the GUI could handle things more gracefully.