OS X / macOS installers going bad

[pcamen]

I've noticed in the last few weeks that when I try to install versions of OS X / macOS from High Sierra (earliest I've tried) and Mojave, the installers are deemed bad with an error message regarding the installer being damaged:



I've tracked this down to apparently being an expired certificate issue:

https://9to5mac.com/2019/10/24/macos-application-damaged/

I've begun to re-download the installers for the various OS X and macOS versions, but this has got me wondering about the long term viability of these versions of macOS as they become "vintage".  What's to say the new certificate doesn't expire in 5 or 10 years? 

Anyone have any thoughts on this? 

 

[Bolle]

Just set the date on the machine you want to install to something in the past when the certificate was still valid.

Once installed it should be fine.

 

[pcamen]

Is it really that simple?  Dang.  I was thinking it was trying to verify the certificate via the internet and that was failing. 

 

[Bolle]

Turn off any interwebs while installing to prevent it from doing that. Not sure how the most recent installers behave but I have installed at least 10.11 using an old installer simply by setting the date back to somewhere to when that installer would have been new.

 

[waynestewart]

I get that if the computer I'm installing it on isn't connected to the internet