Unable to download OS X 10.11 for MacBook Air (2015

Opa-Marc wrote:

I can only download 10.11.06.  Anyone have an idea what to do or where I can

download 10.11?

10.11.06 is a version of 10.11 Apple typically only makes available the latest sub-version of any OS version. You cannot download 10.11.00

Here's the 10.11 download link http://updates-http.cdn-apple.com/2019/cert/061-41424-20191024-218af9ec-cf50-4516-9011-228c78eda3d2/InstallMacOSX.dmg

Here is an Apple article with instructions for downloading various macOS installers.

How to download and install macOS - Apple Support

At this time while running Yosemite, your only options are to download macOS 10.11 El Capitan or macOS 10.12 Sierra since Yosemite no longer has access to the App Store where the macOS 10.13+ installers are located.

If this laptop has any important data on it, then I highly recommend you make sure to have a good backup before attempting to upgrade the OS.

If this laptop at one point did have macOS 10.13+ installed at some point in the past, then try booting into Internet Recovery Mode using Command + Option + R to attempt to access the online macOS 12.x Monterey installer. To install macOS Monterey using Internet Recovery Mode will require having at least 45GB of Free storage space which is only shown in Disk Utility or the System Profiler. Ignore the "Available" value shown every where else since it is misleading and is not synonymous with Free.

Once you install El Capitan or Sierra installed, you can upgrade that early 2012 MacBook Air as far as Monterey.

You may need to make an intermediate stop at High Sierra. High Sierra introduced APFS, and if I remember correctly, the High Sierra installer will automatically convert an internal SSD from HFS+ format to APFS format. The Monterey installer might expect the disk to already be in APFS format for an "in place" upgrade.

You didn't indicate whether that MacBook Air has 4 or 8 GB of RAM. Hopefully it has 8 GB, especially if you are planning on upgrading it all the way to Monterey.

Why would you not want to install OS X 10.11.06? It is the final version of 10.11 and therefore the most stable and bug free version of that system? Please explain.