Upgrade from OSX Mountain Lion without App Store?

_Cassette wrote:

Its not working, because it cant establish a "secure" connection to the server *A website*

That's likely to be a problem with older versions of Mac OS X.

The original security protocol used to prevent eavesdropping on https connections was found to be much weaker than first thought – and there was a movement to upgrade Web sites and browsers. My understanding is that El Capitan has updates to handle that major change (though by now security standards may be tightening again).

Mountain Lion and the versions of Safari that run under it don't. That is why you're likely to have trouble trying to get to any modern https site, including the Apple Community site we're using now, or the Support article which has links for downloading older versions of macOS.

It's possible that App Store security used similar mechanisms (behind the scenes) and that Apple tightened up the requirements for an App Store application to access the App Store in a similar way.

Workaround

Get a USB flash drive that is big enough to hold a .DMG file (disk image) containing a Mac OS X installer.

Using a modern Mac or PC, download the .DMG file containing the El Capitan installer (using the link in the How to download and install macOS - Apple Support article), and put it on the flash drive. Do not try to open the .DMG or create a bootable installer on the Mac or PC that downloads the file. (If the Mac automatically opens/mounts this disk image, quit out of the installer, and eject the disk image, and focus on the .DMG file itself.)

Eject the flash drive. Transfer it to the old Mac running Mountain Lion.

Now you can open (mount) the .DMG file on the old Mac, and run the El Capitan installer inside. (You may want to copy the .DMG file to the old Mac's disk, eject and unplug the flash drive, and use the copy on the old Mac's disk.)

you can visit How to download and install macOS - Apple Support.

once you are there, scroll down to the "Use a web browser for older versions" section. there you will find the download for El Capitan.

_Cassette wrote:

So i try using intall from the app store, but it cost money and it cant connect, Is there any way i can install el capitan?

DO you say what exact MacBook Air 11″ (?) this is...?

ref: OS X El Capitan - Technical Specifications - Apple Support

The macOS/OS X does not cost money—starting with OS X 10.9 Mavericks released 2013

For the App Store you do need to have credit card on the record however

How to create a new Apple ID - Apple Support

El Capitan —

ref: http://updates-http.cdn-apple.com/2019/cert/061-41424-20191024-218af9ec-cf50-4516-9011-228c78eda3d2/InstallMacOSX.dmg

Apple offers installers for Lion (10.7) through Sierra (10.12) in the form of .DMGs. (With the exception of Mavericks (10.9), for which there is inexplicably no installer offered.)

You get the installers for High Sierra (10.13) and later through the App Store. So if your Mac was running Mountain Lion, and was compatible with High Sierra, and you wanted to run High Sierra, you'd upgrade in two steps.

• The first step would be to upgrade to El Captain or Sierra. In this step, you would use a modern Mac or PC to put the .DMG installer(s) you needed onto a flash drive in hopes that this would be enough to keep the old Mac from choking on the https security change.
• Once you had El Capitan or Sierra installed, your versions of Safari and the App Store would likely be new enough that you could access the Apple Support article and the High Sierra App Store link in it directly. (It would still be a good idea to make a bootable clone backup of your El Capitan or Sierra system before trying the upgrade – just in case something went wrong, so you didn't have to start all over again from scratch.)

If all else fails...

https://mrmacintosh.com/how-to-fix-the-recovery-server-could-not-be-contacted-error-high-sierra-recovery-is-still-online-but-broken/

High Sierra “The Recovery Server Could No… - Apple Community