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Qt Online Installer unusably slow on all mirrors



  • I'm trying to install Qt 5.15 Open Source, which you can only do with the online installer.
    For reference I live in Australia, and the default the speed the download runs at is ~220KBps, and the best mirror I was able to find was the Open Computing Facility (all the way in California?) which was only about ~330KBps. I tested that speed with the mirror for the offline sources to see if the installer was the issue, but using the same mirror in the online installer either didn't work or it capped at ~220KBps anyway.

    For the smallest possible download (around 7gb) this is still 8+ hours and I can't pause it or have any network interruptions.

    My internet speed on fast.com is 45mbps down, 20mbps up, and I can typically get up to 2.6MBps downloading pretty much any other file I can find, so it's not my connection.

    I'm not sure what my options are besides just keeping the download running all night.


  • Lifetime Qt Champion

    Hi and welcome to devnet,

    Please check @JKSH helper project



  • @SGaist Hi! I have the same problem here and it says on your link that the project is archived and doesn't work due to new version of qt online installer :/.


  • Moderators

    Hi @SirDigbot and @akuma06, unfortunately it is no longer possible to manually choose a mirror in the online installer. In fact, this has been the case since mid-2017 but I didn't confirm it till recently.

    Please subscribe to the Development mailing list and post there to let the devs know that this is an ongoing problem. Mention these points:

    • Mention that the MirrorBrain service does not always pick appropriate mirrors for you -- other mirrors are often better, so you need the ability to manually pick your mirror.
    • Post the download speed you get from your default mirror, compared with the download speed you get from the best mirror you can find manually.
    • Post your location (if you're comfortable with publishing this information)

    @SirDigbot said in Qt Online Installer unusably slow on all mirrors:

    For reference I live in Australia, and the default the speed the download runs at is ~220KBps, and the best mirror I was able to find was the Open Computing Facility (all the way in California?) which was only about ~330KBps.

    I live in Western Australia and have a FTTN NBN connection. The default mirror I get in recent months is http://ftp.jaist.ac.jp and the download speed varies between ~30 KiB/s and ~200 KiB/s.

    If I manually select http://mirrors.ocf.berkeley.edu/ today I can get ~1 MiB/s.

    For the smallest possible download (around 7gb)

    The smallest possible download is a few hundred MB, which can be feasibly downloaded on a 200 KiB/s link.

    Do not select "Qt 5.15.0". Instead, expand it and only select the version that matches your compiler (for example, "MSVC 2019 32 bit"). The screenshot below shows the different versions of Qt 5.11.0:



  • @JKSH

    I did the download overnight anyway so I don't need further help resolving it, but I'll do that post on the Development mailing list to help others.

    ...unfortunately it is no longer possible to manually choose a mirror in the online installer.

    Post the download speed you get from your default mirror, compared with the download speed you get from the best mirror you can find manually.

    I'm confused, if I'm unable to manually choose the mirror in the installer, am I supposed to test my best mirror speed on the offline sources instead?

    If I manually select http://mirrors.ocf.berkeley.edu/ today I can get ~1 MiB/s.

    Presumably from the offline mirrors? Using the same mirror only gave me 330KBps.

    The smallest possible download is a few hundred MB, which can be feasibly downloaded on a 200 KiB/s link.

    The MSVC 2019 32 and 64 bit for Qt 5.15 are each 7GB so that's what I meant by smallest possible download.