What should I do with MacOS 10.12.6 update that the App Store forgot it downloaded? I'm running MacOS 10.12.4 and I have a time machine backup that’s relatively current. I decided to download the 10.12.6 point update in the App Store. It downloaded the roughly 2 GB file. (I did not see when it finished because I left the Mac unattended near the end of the download.) When I returned to the Mac, the App Store showed 10.12.6 as something I could update, as if I never downloaded it in the first place.  I pushed update and it wanted to re-download the 2 GB update, which I did not wish to do since it takes so long to download. I rebooted and it was the same story.

In /Library/Updates it does show up in a folder titled 091-22861, and if I open macOSUpdCombo10.12.6Auto.pkg which is roughly 1.7 GB it appears to be something that would actually install the update.

I didn't want to run that though since I was afraid doing it that way could mess something up. But at the same time I don't want the wasted space on my hard drive. So my question is, should I run that pkg? Or should I delete the 091-22861 folder? (The folder also contains a couple other pkg files and other minor files.) Also, in /Library/Updates the index.plist references 091-22861 and I would want to make sure that removing 091-22861 wouldn't cause any problems stemming from index.plist either.

Edit: For extra information, I found a website that ostensibly allows you to download the update without the app store, and it indicates six pkg files that you'd need to run in order, and in my 091-22861 folder it only has three of those pkg files. I'm not inclined to install it from within 091-22861 so is there a safe way to erase that folder, and would I need to deal with index.plist in any way?
If you have a partially downloaded and/or installed update for Mac OS stuck on your Mac, you must re-download and reinstall the update on your Mac. You can do this in one of two ways. Either way will accomplish the same thing, with the same results, with no practical difference between either method.


Download the update for Mac OS via the mac app store. 
A second option is to download your update outside of the mac app store by using Apples official download site located at https://support.apple.com/kb/DL1970?locale=en_US . For people who may read this in the future and experience a possible broken link in the above reference, just go to the apple page (or google) and search for Mac OS Combo update download. From Apples website, search or follow the links to the proper (or desired) version (ex:10.13.6) of your update, and download it. The downloaded file should be in .dmg format. Then double click the file, and install the corresponding app from the installer window.


Special Note in regards to Official Apple Software updates:

DO NOT download apple software or updates from a non-apple source.

Once the freshly downloaded update is installed, Mac OS should clean up any leftover files including the "corrupted" or "Partially downloaded" update. 

If this is your only problem you are having with Mac OS, there is no reason to do a full reinstall, even if you are fully backed up. Lastly, I must stress to users how important updates are (primarily for security reasons). You should never get lazy and ALWAYS take the time to install new updates as soon as they arrive in the app store. This will keep you protected, and defended against hackers/rootkits/virus's/trojans/botnets/etc. etc. So please, don't wait, just update the Mac. If for some reason those partially downloaded update files are still there after the update, and if Mac OS doesn't clean up after itself, let me know.