Lately, I have been seen this issue, a lot. Running current beta.
I just started it up to download a TV show I just heard of so no way it is a duplicate. All of the download pieces are listed as "Downloaded" but the directory listed under the "Download Path" is empty. I am waiting for it to time-out and then I will force it to "Download Load - Bypass Filters". I have done this many times recently and it always works.
So, what gives?
I am also seeing lots of incidents where it simply doesn't run AutoPar and then when I run QuickPar manually on the par files it properly fixes the missing pieces and then I manually unrar with 7-zip with no problems.