Hello everybody !
I don’t know where to post this, do not hesitate to move this thread ^^.
I have some trouble with the launcher since a while now.
I bought something on the market place and I had a very hard time in downloading the stuff.
While downloading, the amount of data downloaded come back to previews state regularly : 99.4 Mo → 100,2 Mo → 100.6 Mo → 101.3 Mo → 99.3 Mo…
Of course, it eat my whole (very small) bandwidth and I have to pause the infinite download to make other thing on the internet and… TADAM ! When I paused the download, my bandwidth still occupied by Epic launcher but, the data finally arrived in my hard drive !
By letting the download paused, I happily managed to download my new asset 
Then, the 4.15.1 version come out and I decide to update my UE4.
Same problem ! The download still going forward and back.
I let the launcher running two days (!) and finally had to close the launcher to be able to go on internet and surprise surprise, When I launch my project, I discover that I have the new version of UE4 installed ! But the Launcher don’t know that
Finally, I try to re download the new version but can’t do it (infinite loop again : 24% at 12 and 22% 2 hours later)…
I try to verify it (expecting it will detect that I’m on the 15.1 version of UE but it want to download 2.6 GO of data and can’t do that (it still stuck by 22% since hours).
I try to re install the launcher but the problem remain.
I look at the launcher trouble shooting and try every thing I can (except the DNS server change, I don’t know how to do this).
It’s not very annoying because I can download my market purchase (by pausing the download ^^) and I’m actually working with the last version of UE, even if the launcher don’t know that fact But there’s a problem here ^^.
EDIT : When I look at my resource monitor on windows, I found hundreds TCP connection create by the launcher process and I never succeed at selecting them all to know how many there is. Some of them disappears and some new appears every second, maybe it’s normal (I really don’t know) but Steam doesn’t do that sort of things :).
EDIT 2 : I finally finish the verification of my installation of UE4.15.1. The launcher works all the night and when I woke up this morning, I’ve got a IS-PQE1223 error. I can’t accept the windows UAC because it doesn’t show itself… Maybe it is time limited and if it’s the thing, it’s a huge problem for every person with a poor connection. I can’t spend 30 hours, waiting for a UAC :).
I actually relaunch the launcher with administrator rights, hoping he will not prompt the UAC…
I start the download of the 2.6 Go for the third time, too bad the launcher didn’t write the datas on HD once for all and have to download them again and again at every try…
It’s also annoying that I have to resume the download from the start if I quit the launcher or reboot my PC…
EDIT 3 : Hop ! With admin rights, the launcher works perfectly fine and my problem is solved
BTW, it will be very cool if we had an option to cap the bandwidth used by the launcher (as steam or podcatcher) to keep some of it to do anything else during a large download.
outdated : Is there a way to download updates and market stuff “manually” ? If it is, I will use any download manager and have better result than what I’ve got with the Launcher