[Symptoms]
When installing or updating the package ttf-mscorefonts-installer in Ubuntu 16.04 or 16.10, an error message appears in a GUI window, indicating "failure to download extra data files" (the fonts themselves) "after package installation" (the package itself appears to have been installed). This error message re-appears regularly, as a cron-job re-tries the failed download.
If installing or updating from the command line, additional failure information is given in an error message prefixed by "E:", but this error message depends on the mirror server which is contacted for the download: "404 Not Found" is common, but there is also "Protocol http not supported or disabled in libcurl", and complains about invalid Content-Range headers.
[Cause]
The current 3.4 version of ttf-mscorefonts-installer in Ubuntu 16.04 delegates the download of the proprietary Microsoft Core Fonts for the Web (Andale, Arial...) to the package update-notifier, which itself delegates it to the program apt-helper provided by the package apt. The download URL points to the host downloads.sourceforge.net, which redirects to a randomly-chosen mirror server <mirror>.dl.sourceforge.net.
Unfortunately, the program apt-helper has a bug in the way it treats redirections. This bug makes apt-helper keep a space in the URL instead of encoding it to %20 before contacting the mirror. It is more extensively documented in bug 1655431 and bug 1651923. The mirror replies to this malformed request with an error message (e.g. "404 Not Found"), and download fails.
Some mirrors appear to understand the malformed request nonetheless, and send the requested font file, however since there are 11 fonts to download, the chances of getting 11 understanding mirrors are low. Hence why the error message usually concerns andale32.exe or arial32.exe instead of webdin32.exe.
[Workaround 1]
Download the fonts manually and put them all in the same directory. You can use wget for that, because contrary to apt-helper, it handles redirections fine (command line formatted for readability, do not include line breaks and line indents):
$ wget http://downloads.sourceforge.net/corefonts/
{andale32.exe,arial32.exe,arialb32.exe,comic32.exe,courie32.exe,
georgi32.exe,impact32.exe,times32.exe,trebuc32.exe,verdan32.exe,
webdin32.exe}
Or you can use your browser: point it to https://sourceforge.net/projects/corefonts/files/the%20fonts/final and download the same files.
Make sure the package is purged and no remaining setup triggers are remaining, using your favorite package manager or command-line APT:
$ sudo apt-get purge ttf-mscorefonts-installer
Then reinstall the package, this time pointing to the previously-downloaded fonts in a second step:
$ sudo apt-get install ttf-mscorefonts-installer
# (this will most likely fail again)
$ sudo dpkg-reconfigure ttf-mscorefonts-installer
The second command should return a "graphical" interface in the terminal. Use it to point to the directory where you downloaded the fonts (/path/to/directory/containing/the/fonts). Make sure no .deb files are in this directory, they seem to be picked up too and then it fails.
If a pop-up shows up for a post-install action later, just let it run, it shouldn't come back. It may triggered by the file /var/lib/update-notifier/user.d/data-downloads-failed and you may be successful in avoiding the regularly-reappearing message by removing this file. But this point is less clear.
Once everything is working, you can delete the downloaded fonts in .exe format, they have been uncompressed and installed in /usr/share/fonts/truetype/msttcorefonts in .ttf format.
Adapted from: Vincent Gerris (comment 17), Lesley Binks (comment 18).
[Workaround 2]
Remove Ubuntu's version of ttf-mscorefonts-installer and install Debian's version instead. Indeed, Debian's version uses wget to download the fonts, and contrary to apt-helper, wget handles redirections fine.
Download the package from https://packages.debian.org/ttf-mscorefonts-installer. Version 3.6 has been tested by several users. This workaround should work with Debian's version 3.4+nmu1 too, but then you'd be prompted to update to Ubuntu's problematic version 3.4+nmu1ubuntu2 next time you update your packages.
To download the package with wget (command line formatted for readability, do not include line break and line indent):
$ wget http://httpredir.debian.org/debian/pool/contrib/m/
msttcorefonts/ttf-mscorefonts-installer_3.6_all.deb
Purge your currently-installed Ubuntu version of the package using your favorite package manager or command-line APT, and install the Debian version with dpkg:
$ sudo apt-get purge ttf-mscorefonts-installer
$ sudo dpkg --install /path/to/ttf-mscorefonts-installer_3.6_all.deb
When this bug is fixed in Ubuntu 16.04 and 16.10, you can uninstall Debian's version of the package and go back to Ubuntu's version:
$ sudo dpkg --purge ttf-mscorefonts-installer
$ sudo apt-get install ttf-mscorefonts-installer
Adapted from: yas (comment 19), Richard Elkins (comment 40)
[Fix]
The bug was fixed by Julian Klode in package apt-transport-https 1.4~beta3ubuntu1, released 2017-01-11, for the then-upcoming 17.04 (zesty) release, see bug 1651923 comments 24 25.
The fix was backported to apt-transport-https 1.3.4 and 1.2.19, released 2017-01-26, for the previous 16.10 (yakkety) and 16.04 (xenial) releases, respectively, see bug 1651923 comments 57 58.
If you are still affected by it, update apt-transport-https to the appropriate version and reinstall Ubuntu's version of ttf-mscorefonts-installer. Reinstalling is necessary or the daily error message won't go away, see bug 1654573 comment 12.
You should also remove Debian's version of ttf-mscorefonts-installer before reinstalling, if you installed it for workaround 2 above:
$ sudo dpkg --purge ttf-mscorefonts-installer
[Important remarks]
If you run into Content-Range errors when reinstalling ttf-mscorefonts-installer, remove the downloaded fonts in /var/lib/update-notifier/package-data-downloads/partial/ and try again. This is a different bug, fixed by Julian Klode in package apt 1.4~beta4ubuntu1 released 2017-01-25 for the then-upcoming 17.04 (zesty) release (see bug 1657567 comments 1 2), fix that was then backported to apt 1.3.5 and 1.2.20 released 2017-02-27 for the previous 16.10 (yaketty) and 16.04 (xenial) releases respectively (see bug 1657567 comments 14 16). You shouldn't run into this bug if using these versions.
You may also run into warnings about a user _apt and their privileges: these are non-blocking and don't impact the successful download and installation of the fonts, as you can check at the end of the installation log. They have been reported in several other bug reports (e.g. bug 1658707), but not investigated yet.
This bug used to be a duplicate of bug 1651923, but it has been de-duplicated to hopefully make it easier for people to find it, instead of reporting the issue as a new bug. Otherwise, duplicates are hidden.
Status changed to 'Confirmed' because the bug affects multiple users.