Hi,
It seems I can’t download 4.2.1, it’s stuck at 32%, and after a while it fails.
I can install 4.1.2 though… 
I’ve tried increasing the timeout like said here [Official] Read this if your Download has stopped around 81% - Getting Started & Setup - Unreal Engine Forums but didn’t work.
Attached is the UnrealLauncher log file.
Specs:
Win 7 Pro SP1 x64
Intel Xeon CPU E5-2650 v2 @ 2.60GHz
32GB Ram
just added the log file as a txt file. site doesn’t allow .log extensions.
Hi rvc,
Sorry to see you are having problems, and thanks for the log, it’s helpful.
Looks like for some reason some of the patch data is not downloading correctly - the same file parts repeatedly download smaller than they should.
I’m wondering if there is a problem with the file on the server you are connecting to. Could you run something to help us identify which server you connect to? Open up a command prompt (Win+R, type “cmd” press enter) and run the following:-
nslookup download.epicgames.com
And paste a screengrab of the result.
Thanks!
Leigh
Thanks for looking into 
C:\Users\rvc>nslookup download.epicgames.com
DNS request timed out.
timeout was 2 seconds.
Server: UnKnown
Address: fe80::c605:28ff:fe23:df47
DNS request timed out.
timeout was 2 seconds.
DNS request timed out.
timeout was 2 seconds.
Non-authoritative answer:
Name: d24lpxjd18u31u.cloudfront.net
Address: 54.230.24.174
Aliases: download.epicgames.com
download.ol.epicgames.comI am having the exact same issue. A clean download (not update) is getting stuck at the same point, I got the same nslookup result.
I’ve actually managed to download everything yesterday. I’ve spent the day pressing install and eventually it passed that chunk. 
So I can’t update/install again with higher verbosity. But maybe BaderThanBad can.
It does seem as though there may be a problem with a specific node, we’d require some further information to identify exactly which node it is causing this problem. Could you produce a log file for us with a higher http logging level? In the DefaultEngine.ini where you changed the logging to Log, could you make it VeryVerbose.
[Core.Log]
LogHttp=veryverbose
LogOnline=veryverbose
You’ll probably have to zip the log file before uploading.
Also, be sure to switch this back after generating the logs otherwise you will end up with many spammy log files on your system
Thanks rvc, I added another answer, could you try that too? Hopefully we’ll get to the bottom of this!
Hi BaderThanBad, could you post a log file so that I can confirm you have the same issue?
Hi, I produced a very verbose log that I am attaching. It does seem that a certain chunk is failing to download. link text
Thanks BaderThanBad! I’ve contacted our experts so I should be able to update you soon
Hi again, we have been in touch with amazon who have checked the file their end on the node you connected to, they say it looks fine. Are you still hitting the same issue now?
Yes, I am still having the same issue.
Ok, one of our engineers has issued an invalidation for the two files that appear to be failing for you. It could take some time to go through, maybe an hour or two.
Could you have another go and let us know? If you still have problems, throw me another log if you don’t mind, in case you hit some other file issues.
EDIT: It went through quickly, you can try asap
Sorry for the late reply, I was not online yesterday. I am sorry to say that the issue still seems to exist for me. I however have a compiled version of the source so I will just wait for the next update released with the launcher and hopefully it will go through.
Sorry to hear that.
Can you get us a fresh launcher log so we can see if its the same chunk or something different?
having the same problem again to download 4.3 preview :S
failing on:
http://download.epicgames.com/Builds/Rocket/Automated/Engine/CloudDir/ChunksV3/63/F4812D8FB88645DF_7E917C2C4D827AF6BE726F9B8B8AE8BE.chunk
and
http://download.epicgames.com/Builds/Rocket/Automated/Engine/CloudDir/ChunksV3/69/E787A352C218F732_546469E146D72F20C45B7EBD4EADBFE3.chunk
I just noticed that I can’t download any of those chunks but if I try:
it works.
If I change the URL of the failing chunk from this:
To download.ol:
http://download.ol.epicgames.com/Builds/Rocket/Automated/Engine/CloudDir/ChunksV3/63/F4812D8FB88645DF_7E917C2C4D827AF6BE726F9B8B8AE8BE.chunk
It works.