KDE does not currently provide binary downloads for Mac OSX. Instead you need to build KDE for yourself from source. The easiest way to do this is to use one of the Mac build systems which will automatically resolve all the dependencies for you. Unfortunately, this can be a very long process, taking up to 2 or more days. As at December 2012 MacPorts is currently recommended as it is the most up-to-date.
As of September 2013, MacPorts has KDE SC 4.11.1, and KDE 3.5.10. Note that KDE3 is unsupported by both KDE and MacPorts.
Instructions are provided on TechBase for installing a development environment using MacPorts. If you want a user installation then just skip the final 'Configure your KDE development environment' section.
As of December 2012, Fink has KDE 4.4.1 and KDE 3.5.10 available for installation. Note that KDE3 is unsupported by both KDE and Fink.
The Fink packages allow you to install KDE4 as either Qt/X11 or Qt/Mac (native) packages by selecting either packages ending in "-x11" or "-mac", for example "kdebase4-x11" and "kdebase4-mac".
Additionally, the Fink packages allow the running of the Plasma desktop in X11 mode. Just install "kdebase4-workspace-x11" to install it.
The Fink KDE packages will be installed in /sw/opt/kde4/x11 or /sw/opt/kde4/mac respectively. They also are able to start D-Bus for you as long as you run "/sw/bin/init.sh" normally, or when you open a terminal, if you have run the path setup script in the Fink installer.
As of Dec 19th 2012, Homebrew recipes has been updated with KDE 4.9.4 and 4.9.95 packages url and sha1
I have not throughly tested since 4.8.0 but I had Amarok window to open and some bugs we're left.
If you want to help out. please fork and open PR against my repo. I will test some more soon.
Note that when a new KDE release comes out, most recipes can be updated automatically using my script https://github.com/somekool/public_scripts/blob/master/bin/public_scripts/update_kde_versions
Calligra has a standalone homebrew tap which brings least kde dependencies when installing calligra, here are the instructions to use it.
You can tap this repository into your homebrew. It adds KDevelop and Kate packages (and all their dependencies). At of Oct 10th, 2013 the repository has only those two applications. More planned.
Please carefully follow installation instructions.
Some KDE applications provide a standalone installer, usually in a Qt only mode and missing some KDE integration features.
The applications should be run from the Finder or via Spotlight. See the MacPorts or Fink sections for where the applications will be installed.
Before running any KDE apps you need to perform a couple of steps once only (replace $USER with your username):
sudo chown -R $USER ~/Library/Preferences/KDE sudo launchctl load -w /Library/LaunchDaemons/org.freedesktop.dbus-system.plist
Sometimes, Installer.app fails to run the post-install. If things are acting funny, try running these two commands in a terminal:
sudo launchctl load -w /Library/LaunchAgents/org.freedesktop.dbus-session.plist /opt/local/bin/kbuildsycoca4
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