I have Mac Pro (Mid 2010) Processor 2 x 2.66 GHz 6-Core Intel Xeon, Graphics ATI Radeon HD 5770 1024 MB, it has OS X Yosemite 10.10.2 and i want to install OS X 10.7 but i can not install, please help?

There is no six-core spec model Mid-2010, but there is one for Mid-2012.

The Mid-2010 has different processor configurations, neither of them six.

(Either four-core or eight, is what shipped in the Mid-2010 sales model)

If your computer shipped with Lion 10.7, it would be one of these versions,

and that is only if your Mac Pro is the Mid 2010. (not six core)

Original OS Mac OS X 10.6.4 (10F2521, 10F2554)

Later OS Mac OS X 10.7 (11A511a), 10.7.2 (11C74), 10.7.3 (11D2001)

Double check the model build series sales information & identify this correctly.

This would be Mac Pro (Mid-2012) with either Four, Six or Twelve core processor:

Original OS Mac OS X 10.7.3 (11D2001)

Later OS OS X 10.8 (12A269), 10.8.3 (12D78)

as noted from http://mactracker.ca specs and http://everymac.com online info

You should be able to match the serial number with the model sales spec to see

what was shipped with the computer. I've asked the host to move your Mac Pro

post to there, since it is not a PowerMac G5 architecture; yours runs Intel cores.

Good luck & happy computing! 🙂

There were 2 12 core 2010 Mac Pros in the Server edition...

http://www.everymac.com/systems/apple/mac_pro/specs/mac-pro-twelve-core-2.66-mid -2010-westmere-server-specs.html

http://www.everymac.com/systems/apple/mac_pro/specs/mac-pro-twelve-core-2.93-mid -2010-westmere-server-specs.html

And then mine...

Hardware Overview:

Model Name: Mac Pro

Model Identifier: MacPro5,1

Processor Name: 6-Core Intel Xeon

Processor Speed: 3.46 GHz

Number of Processors: 2

Total Number of Cores: 12

L2 Cache (per Core): 256 KB

L3 Cache (per Processor): 12 MB

Memory: 32 GB

Processor Interconnect Speed: 6.4 GT/s

Boot ROM Version: MP51.007F.B03

SMC Version (system): 1.39f11

SMC Version (processor tray): 1.39f11

Hmmm, what happens when you try?

Are you trying to install to a new drive or empty partition?

And so? That's like saying I have a 2x 6 volt battery in my car.

With only 6 x 2v cells. How many cores vs total x processors.

I see your point. However the main specs give the total cores.

Why give half the specs and expect a whole answer? 😝

Without knowing ow you you tried to install it and what happened when you tried:

You need to obtain a copy of the install for Lion. If yo purchased it before you can go to the Purchases section of the Mac App Store and download it.

Otherwise you have to purchases via

http://store.apple.com/us/product/D6106Z/A/os-x-lion

Then make a bootable USB install media using

DiskMaker X

Boot from the install media and format the HD and install.

WHY do you want to do this?

10.7 is old and is not getting Security Updates. If you can run Yosemite, 10.10, that is what you should be running.

Almost everything that says, "requires 10.7" actually means, "requires 10.7 OR LATER" and will work fine.

You can configure any 2009+ to have dual 6-core or just 6-core.

Some people say tomato. You can't have one processor be different than the other in a pair, and there are lots of ways to configure.

How many hard drives do you have installed that contain a bootable OS? If you only have one bootable drive, with Yosemite installed on it, and you try to get Lion from the App Store, you will run into problems.

More detail from you would help.

I think all the other replies have missed the point.

Firstly you may find that will need to erase your Yosemite disk unless either you have a second disk you can use or an create an additional volume on that disk to use. Disk Utility will let you add an extra partition and shrink the existing one if there is enough available space.

Once you have decided whether you are willing to wipe the existing disk or have another disk or volume as above available you could try the following.

1. If not already done download the Lion installer from the App Store i.e. OS X 10.7.5, I can confirm this version of OS X is compatible with 2010 Mac Pro models, no matter how many cores they have
2. Then download DiskMaker X from here http://diskmakerx.com
3. You will now need an 8GB or bigger USB memory stick
4. Use DiskMaker X to make the USB memory stick into a bootable OS X installer drive, DiskMaker X will ask you which version to use - in your case the 10.7.5 you have downloaded as above, and will then copy it to the memory stick
5. Once DiskMaker X has finished, you then need to boot from the memory stick by holding down the Option key when you turn on your Mac and selecting it
6. Once booted from the memory stick you should be able to either erase the Yosemite drive (or if needed a different drive) and then begin the installation process

....

Yes, once you have a later OS installed, downloading an earlier one becomes problematic. To get the 10.8.5 installer app a while back, from which I wanted to make a backup flash drive installer to replace my 10.8.2 installer, I had to boot from a Snow Leopard drive with no backed up Mountain Lion installer on it, and unmount the other HDs that had later OS versions installed, or backups of installer apps. I assume that this difficulty is an attempt at idiot-proofing on the part of Apple, but it really makes things unnecessarily complicated at times. And the App Store gives no useful info in its error messages.