Flushing to Disk

I've been having this issue at random times, with random files. where it gets to 99.8% and then it changes to says "Flushing to Disk" and then it just stays that way, i let it sit for an hour once and it didn't change at all. I've been using uTorrent since i was 17 and I am 25 now almost 26, so been a user for quite awhile, and i have never ever seen that term or had this issue. From what I can gather, it has to do with bits of the file being determined as dirty and those bits being buffed to try and make them not dirty and download it anyway. But I am still not quite sure what that means. I've been a Custom PC builder and Programmer for quite awhile as well and never heard that term in my course of Building and Programming. So if anyone can enlighten me as to what that means, as well as any possible way to fix it, if there is one, or am i just gonna have to not download that file and find a different upload of what I am trying to download ?