Mac Pro 3,1 boot issues


macrumors newbie
Original poster
Jun 7, 2010
Växjö, Sweden
So I recently got my hands on a Mac Pro 3,1. It was missing RAM so I bought some 667MHz from Ebay.

Here's my problem; it boots, but when I select my El Cap usb install disk the mouse pointer freezes and nothing happens. I've tried three different flash drives and reset SMC and PRAM.

Also, when I press the power button there's a single clicking sound from the case. Same when I press it to power off.
Last edited:


macrumors 65816
Dec 22, 2012
I have never had any success with booting either of my 3,1s from a USB flash drive. I'm not even sure that it's possible. Just use an external disk. I have a couple of 500GB self-powered FireWire 400 drives that I use if I ever need to boot from an external device.


macrumors newbie
Jan 29, 2017
I was never able to get my 3.1 to boot from usb as well, would always just lock up, or restart mid install. It did this on OsX installs as well as Windows boot camp installs. Was able to get around it by doing what nigelbb said, and just putting the image of OsX I was going to install on a spare internal drive. Or in the case of getting Windows on it, taking the boot camp drive out, putting it in a Windows computer, starting the Windows 10 installer up until it said it need to restart to complete the installation, and then at that point pulling the drive and putting it back in the mac to finish the install.

Think it has something to do with booting and the EFI not being compatible/friendly with the installers, but that's just a guess.


macrumors 68000
Dec 12, 2005
how did you make the boot drive?
can you try a different version of osx?