Mac Pro 4,1 Not Support Mavericks?

Open Terminal and copy and paste this line:

diskutil list

then press return.

then copy and paste the output here.

I know I've read reports but whether it is bluetooth or wifi card issue... something. tried google?

Are you trying to erase the drive first?

There is a bug in 10.8.4, 10.8.5, and 10.9.0 Disk Utility ERASE function.

Tip for No Drives Seen in Mac Pro by OS X 10.9 Installer

Saw 2 recent threads in Apple's forums from some Mac Pro owners (2009/Mac Pro 4,1) that said they could not upgrade to OS X 10.9 because the installer didn't show any hard drives to install on. One affected owner said removing the Wifi card solved the problem. No posts there (yet) listed which WiFi card model/chipset they had, but those posts reminded me of a similar problem with the OS X 10.8 installer on 2009 Mac Pros if an older 802.11a/b/g Atheros WiFi card was installed. Rare since most use the Broadcom based 802.11n card (a/b/g/n) like Apple OEM'd with the Mac Pro. (The 2009 Mac Pro Airport card is mounted on the motherboard behind the removable CPU tray.)

Here's a link (from the Tips page, OS X section) to the Oct. 2012 post on Mac Pro OS X 10.8 Upgrade problems due to (old) Atheros WiFi card conflict w/SATA. I'm guessing (from the 2009 Mac Pro/10.9 installer post) that the same issue is seen with OS X 10.9 installer if that older card is installed. (Rare I suspect as most 2009+ Mac Pro owners have the 802.11N Broadcom card, as generally only DIY upgrades may have installed an older WiFi card and even then the broadcom is most common.)

http://www.xlr8yourmac.com/

I had this same problem with a Mac Pro 5,1 2010 model. I was unable to install Mavericks or Yosemite. It worked normally with Snow Leopard. When I tried to boot the 10.9 or 10.10 installer, the white and grey apple logo turned into a circle with slash (forbidden) symbol. I tried removing drives, RAM, etc troubleshoot. I found I could boot from a 10.10 installer on a USB drive, but only if SATA bay 1 was empty. The installer could not see any internal SATA devices which meant I had nowhere to install 10.10. I moved one of my drives to a firewire SATA dock and was able to install 10.10. It booted fine into 10.10 although a bit slowly via firewire and it would not recognize any internal SATA devices. System Profiler listed the SATA controller but all the devices were listed as unknown. I then moved the drive to internal SATA bay 1 and of course it would not boot. I saw a gray screen with a progress bar which hung about one-third of the way through. Then I got the forbidden symbol and had to force the Mac Pro to shutdown. I was ready to lug my system to the Genius bar when I found this thread.

The WiFi card in the Mac was an Apple AR5BXB6 dated 2006. The circuit board also read Atheros Communications 2005. I bought this mac used so I guess the WiFi card was added or replaced by the previous owner. Once I removed the WiFi card, the Mac booted fine into 10.10 and all SATA devices were recognized normally. Now I'm wondering is there is a compatible driver for this Airport card . . . .