This is where you need to recover your system using SFOTT. That works just fine, until Mavericks fails to start (I ended up in my old Lion system on a reboot, if you have no other system installed your computer with probably just not start).
I used App Store to upgrade Mavericks to 10.9.5. Video will work, but with problems (try Safari, and you will see), and Audio will not work. After about an hour you should have a clean 10.9.0 Mavericks with network/wifi working. To start the computer from the USB-drive, hold down the “alt”-key (not Apple-key, not ctrl-key) while starting the computer. Installation of Mavericks from the USB-drive is very standard. There is if course no true guarantee that a future Apple upgrade will not break everything completely. I did the entire procedure on my working Mavericks just to test it, and it seems fine. Run SFOTT.sh and you can re-Patch your broken Mavericks system. Find the SFOTT.app on the key, and find SFOTT.sh inside SFOTT.app.
If you can not do side-by-side you can start from your SFOTT-key (which you still have) and instead of installing Maverick you start the Terminal application. I installed Mavericks on a separate partition, side-by-side with Lion, so when Mavericks failed to start my computer automatically started Lion instead and I could run SFOTT in Lion to re-Patch my Mavericks system.
When Mavericks fails to start you need to “re-Patch” using SFOTT. Minor upgrades to applications or security upgrades should not cause need to recovery. Nobody knows about 10.9.6 of course, because it is not out. My impression (after reading different sources) is that this recovery is needed when upgrading from 10.9.0 (or 10.9.1 / 10.9.2) but not later. When upgrading from 10.9.0 to 10.9.5 like I did, it will not boot.
When you install a Mac OS upgrade there is a risk your Mavericks system will not boot. Use the autorun mode to create the drive. It will take some time to make all the settings in SFOTT (it took me perhaps 15 minutes), but it was self-explanatory and not very difficult. SFOTT is a self guiding menu-driven application. You simply double-click on SFOTT on a Mac where you both have your Mavericks Install App and your USB-drive. You first need to use SFOTT to create your bootable USB-drive (it is called “key” in SFOTT). The 7z-file can be opened with StuffitExpander, that already Should get the file mac-mini-mavericks.7z. Where to click to get the right thing, and what gives you spyware. Warning, this is one of these horrible download pages where you don’t know
YouTube-video (etc), works occationally (now worse than in 10.7, my experience).The build-in web camera – “works” but not as it did in 10.7, I think.Sleep mode – not working at all – leave on or shut down.I want to first write what does not work: