is there a reason GOG downloader utility continually re-downloads files after I've already got them? It is somewhat time consuming and it does so every time I open it after I've closed the utility. I will buy a new game, and then go fetch it from GOG and open my utility but it re-downloads my huge library before getting my new games. The re-downloading is somewhat quicker but is still time consuming as I have dozens of games now.

That shouldn't be happening- do you log out of the downloader after you're done? It should remove all the previous downloads.

You need to clear it.

You have to clear the list of downloaded games.
There's a "clean" button on the top next to "pause all" and "resume all" buttons.

It doesn't redownload all your games though. It checks if you have the latest versions downloaded. If not then starts downloading the new files.

when I clear it, it will remove all the installers/extras from the folder I downloaded it too. It doesn't always clear the cache sometimes I will relocate my backups to a new directory via cut/paste and then uninstall the download utility then run ccleaner, reinstall it later if I buy new games.and it will begin redownloading old games, sometimes exe installer files are not there sometimes they are, the contents it redownloads are random(as far as I know). The Witcher RedKit tools often gets redownloaded reguardless of whether I clear it off the cue or not. I've found the only way to clear it is to go online(sometimes I do it offline-but when I go back on it just replenishes the cache) and individually right click/"remove from list" that is, after I relocate my backups/extras to a different folder that the tool can't "see". since it clears the original location.

generally, yes, I sometimes uninstall the thing when I'm not planning on buying new ones for a while. the problem is when I chose to buy new ones I go to retrieve them and it randomly starts redownloading some (or sometimes more or all) of the old ones. mostly it's "The Witcher 2 and its extras but other games get caught in there at times.

Uninstall, redownload and reinstall it? Do you log out of the online site or are you always logged into that too?

What JMich said. You may also want to check setting is not set to startup with windows.

I have taken everybody's suggestions into serious consideration and have spent some troubleshooting time, however this particular copy is not as glitchy as the previous one(even though they are the same version) I now have a "clear" button where as before-my other copy of the GOG tool, it was greyed out when the thing was still insistently downloaded old downloads. I never thought to clear my Appdata nor sign out of my account/gog installer before uninstalling. So next time the program acts up will try this trick-I did so now anyway to be sure it would not act up none-the-less.. I have also found that if you try and clear offline it doesn't "communicate" with GOG website(only speculating) and thus the cache will replenish when I reconnect. I suggest also(to any who have this problem aside from me) to go online before clearing the files and place back ups in another directory so they aren't removed. However this time, the files were NOT removed from my original directory. Why they were last time I will never know. Thanks to all of you for the help and I am very grateful for all the thorough replies. I think it works correctly now, although I have no idea why the "clear" button was disabled on my other copy that I had loaded not more than a week or two ago(same version).
again thanks! I think I'll go download my new Risen 1&2 collection now-that I just bought! :D