App Store Download Progress Stuck – How to Resolve

I spent a long time with customer support on this; several weeks actually.

One of the things you can try is to remove the folder that is listed in the console log when the issue happens. To do this, open console and leave it running. Next attempt the download and when you get the failure message, go back to console and you will see entries which say that system was unable to access a folder. Using finder, open the folder just above the folder that is named with a random sequence of strings.

For eg: file:///var/folders/nc/qmbww7hd0cl24ylyqnldqxv80000gn/C/com.apple.appstore/409183694/mzps155989934935175015.pkg#Keynote6.pkg

In the above case, delete the folder nc. Make sure the appstore is closed when you do it. Restart the computer after this.

But what really fixed the problem for me was a very simple change.

Click on the wifi symbol on the menu bar and click open network preferences. Click on the location drop down and click edit locations. Remove all the locations in the resulting window and create a new one with a completely new name.

Restart the PC and connect to your network and attempt the download again. This fix is what worked for me. In case you have the same issue, try it out and let me know if it worked.

I see several issues with different solutions. Let's try to fix them one at a time

Spotlight

First you should check if your Spotlight index is current. Search again for the Sierra Installation App. If it is listed, scroll down that list and click on "Show all in finder" (see Apple Support Page Description).

You get a Finder Window with all the Search results and if the Installer App is listed there you can get the Location and try to create the bootable USB Stick from there. You should also check the File Size and the Permissions of the Installer in case it is f.e. File Size 0 or you don't have permission to execute the Installer. You could also delete that Installer in order to reload it from the App Store.

If the Installer is showing in Spotlight, but is not showing up in the Finder you should rebuild your Spotlight Index (see Apple Support Page here or use a third party tool like Onyx, but be carful). Depending on your HD Size and Speed that could take some hours.

App Store

If the App store is still showing that the installer is present and won't let you download, you could try to delete (or just move it somewhere) your App Store Cache at ~/Library/Caches/com.apple.appstore. You should restart at that point and then try to Download from the App Store again.

There is a second (temporary) cache Location but only for downloads. You can get there fastest by opening the Terminal and typing in open $TMPDIR../C/. There you will find a Folder named com.apple.appstore which you could also move, restart, then try to DL again.

Try these approaches first and see if that solves your Problem.