Logic Pro X was not able to complete the download. Check your internet connection and try downloading again.

I had the same problem while downloading the “Essentials” package from home (Frontier, formerly Verizon). Connected my MacBook Pro to a different network near my job (Brighthouse), and the download was successful.

The Apple Pro Apps tech I spoke with suggested I do that, because they’ve seen that problem before, and it appeared to be some kind of problem with my ISP.

David, I have had posted the same question a year or so ago and had absolutely no proper answer... just last week I had a major problem with the Sierra OS (terrible OS by the way... way too "heavy") and I had to reinstall everything, and I am still having the same problem as you have.

What I did the first time I had it and now was enter the Download Manager and select one by one and download separately… It ***** big time, but this is the only way to get as many items as possible, but still, it doesn’t fix the problem, because there will be a few items that you will not be able to download no matter what you do…

Still, if you notice in the LIBRARY window on Logic (press Y), the missing stuff will show a small arrow pointing down, you can still try clicking on them, but still doing it one by one…

I hope this will help you get any further, cause ever since I first had this problem, there was not one single person that would give me a helpful answer and, most of the time, actually really trying to blame the internet connection or the hardware…

Some ISPs place limits on the per file size of files downloaded from the net.... (Though I don't believe Verizon does so but it's Verizon so who knows.. they change things so often it's hard to tell.. depending on the package you have bought from them...!) or time out during such transfers of larger files.. or certain routers just failing to keep awake during such single file downloads... which then drops the 'signal' so to speak so the download times out... or it could even be a routing issue.... and may fix itself later...

It could also be your Mac is going to sleep or sending the drives to sleep and the touter isn't correctly responding to such behavior.... So, make sure your Mac and it's HDs are not going to sleep during the process....

Finally, an obvious one.. but often overlooked.. make sure you have plenty of free space on your System Hard drive.. as a lack of it.. and therefore a lack of space for the files to both download and then install... can cause such issues.. Note: OS X prefers at least 30% free space on the system drive at all times to function optimally.

Failing all of that....

Check the tips in the following link..

Downloading 'Essential or Additional Content' or the Logic Pro X app Tips

Make note of each of them as they have al been found by one user or another to resolve the issue...

...and the available space on your system HD is?

You set the Energy settings for your Mac so the HDs don't go to sleep and the Mac itself (not just the screen) stays awake?

You tried using Ethernet instead of WiFi?

If its not any of those then it's likely going to be an issue with your router or your internet connect or ISP.....

To test, upload a large 1.8+ GB file (anything will do... Zip up a load of files until you end up with a very large file) to Dropbox and then try downloading it again yourself...

I didn't realize that on newer Macbook Pros there isn't a Computer sleep option any longer....

Mine looks like this.....

So.. apart from trying with Power Nap off.....

Based on your answers it has to be something to do with your Router and/or network related issues... (assuming you also repaired permissions?)

Cant think of anything else.... at this time...

FWIW, in the past with other clients that had this sort of problem.. it's always been down to the router, network, disk related problems.. or sleep settings that were found to be the cause of the issue... I have never come across another reason.

Ah.. it was the router (one of the most common reasons for such issues)

If I may ask.. how did you resolve the problem?

Switch routers.. eliminate it from your network temporarily... reboot it?

David, I have been struggling with this very problem for about three months. I have tried so many variations (very frustrating) and I'm about to completely delete logic and try re-downloading it if switching the router doesn't work (even though I really don't want to because I even experience many problems just installing Logic). Can you tell us how you fixed it? Did you get another router or did you reboot yours?

Just tried downloading again with ethernet plugged in, all other apps closed, energy setting properly adjusted to not fall asleep or dim the screen and disk permissions repaired. I'm going to try to take my Macbook to my friend's this weekend for band practice and try using his router there. If that doesn't work then I will sell this laptop to buy an authentic Wakisashi and commit Seppuku at sundown.