Where to get older OS X installers?

[desertman]

I collected over the years from the various Macs that I owned the OS X installers for versions 10.6 through 10.11.

However, when I tried to use the OS X 10.7 installer on an older MacBook with 10.6 (to make it "iCloud ready") I got an error message, saying that this installer was too old (or something similar) - and I could not use it. I then faintly remember that I read some time ago that Apple "disabled" all (or some?) installers from some (or all?) OS X versions and replaced them with newer versions.

Is there any way to know which installers work or not work without actually trying to install these versions? Is there a way to get new installers without having to buy them new? When did Apple start to offer OS X versions for free?

Thanks for your help!
[doublepost=1462237912][/doublepost]I just found the article about here on MacRumors about the expired Developer Certificate (https://www.macrumors.com/2016/03/03/older-os-x-installers-broken-by-certificate/). This means there seems to be a "remedy" to still use the old installers. Did anybody try this and can confirm that it works? (I will try certainly myself tomorrow.)

I then also found all OS X versions from OS X 10.8 Mountain Lion in the Purchased section of App Store on my Mac - but I cannot re-download them (except for OS X 10.11). Is there a trick to download them again?

 

[CoastalOR]

The App Store will only let you download the purchased full installers on Macs that are capable of running that OS. It may be because the installer automatically launches after the download. I ran into this same issue when I tried to download the OS 10.8 installer on my 2015 MBP and it was not allowed. I went to the 2011 MBP for the download and there was no problem.

 

[Ebenezum]

I just found the article about here on MacRumors about the expired Developer Certificate (https://www.macrumors.com/2016/03/03/older-os-x-installers-broken-by-certificate/). This means there seems to be a "remedy" to still use the old installers. Did anybody try this and can confirm that it works? (I will try certainly myself tomorrow.)

Terminal instructions provided in the article are correct. If you plan to install the OS to several computers its probably good idea to download new copy of the installer so you don't have to use Terminal every time...

Regardless one hopes Apple would take heed of this mess and design a foolproof installer method.