Well I think this is not a bug but rather a "missing"(?) feature. I did some testing with ewido encrypted signature files trying to crash the application.I had no luck that far with my experiments but whenever I will find free time I will try some more tricks. But I noticed something weird and potentially dangerous. If all the database files are deleted then when the program is launched while it is reported in the main page that the number of signatures are 0 there is no pop up message reporting that to the user who may not notice it! Note that I've disabled auto updates . I think that if the program cannot load any signatures the user should receive a message and be prompted to download them since this is major security risk for signature based security software.