El Capitan upgrade from an old MacBook pro.

pull the serial number from inside the battery bay if separate, and if not the bottom of the laptop and insert in the field on this page:

http://checkcoverage.apple.com

Report back to us the year, time of year, and make of the machine. This will tell us what what is possible. Do not report the serial number on the communities page.

Early 2011 MacBook Pro is sort of a limbo model.

It is not guaranteed to run internet recovery, as it needs a special firmware update to use it.

It does not support any retail release of Mac OS.

It must have one of the following to install Mac OS:

1. A bootable external USB or Firewire hard drive with 10.6.8 through 10.13.6

• If available Carbon Copy Cloner or Superduper can clone to the internal hard drive for internal use as long as it won't be used by another computer.

2 The original MacBook Pro 10.6 installer disc that is designated for 2011 MacBook Pros. It can't say OEM, DropIn, or another Mac model.

3 After connecting to power and ethernet on a modem boot from command-option-shift-R and reveal the recovery installer. This would mean the aforementioned firmware was installed.

4 Having a bootable copy of any Mac OS 10.7 through 10.13.6 on an external drive, you can run the upgrade to El Capitan, Sierra, or High Sierra using the directions on upgrading 10.11 and its referenced pages. You can't run the installer of an older OS from a newer OS. The installer will then recognize the installer disc if not damaged and allow you to install the OS on it.

The do not enter sign means the current installation is neither supported, or is corrupt or damaged as a bootable drive.

If you boot with the Option key it may reveal other boot partitions you can try to use, if the drive has other boot partitions. If not, then one of the above 3 is needed. The installer will let you open the Disk utility and format it HFS extended, and wipe the contents of the drive. If you have the original installer disc, the Option key will be able to boot that at startup if inserted. Same thing then, if the hard drive is working you can install the operating system from the installer.

10.6 needs to be updated to 10.6.8 Mac App Store before upgrading to 10.11.6.

Combo v1.1 (7/25/2011),

Thunderbolt update for 2011

iMacs and MacBook Pros for installation after

10.6.8.

10.6.8 2013 Security Update 004,

2013-005 Java update

All need to be updated before upgrading 10.11, if all you have is 10.6.

If running 10.12 or later, you will not need 10.11 for anything as most software is designed to run on something newer in anycase. Options 1 & 4 are only available if you have another older Mac to create that external drive from.

Not a CD. https://support.apple.com/en-us/HT202860

I have found them not to be reputable.

http://www.macsales.com/

http://www.dvwarehouse.com/

are both better for older equipment.

The big question is how much older software do you have that runs on El Capitan that you can just redownload from the App Store? Backed up to external drives like Time Machine? A lot of that will make the difference which intermediate machine would get data from your old backup to your MacBook Air, and how much you'll need to use an older Mac for old applications that can read your older documents.

https://www.ebay.com/str/macofalltradescom

I found them to be quite reputable.