

Her iMac is on a different floor from her router, so I have to use Wi-Fi.When I tried to install it via USB, I got an error message that I didn't think to write down, but I'm pretty sure that it said this OS couldn't be installed on this computer. The Apple Support site says that El Capitain can be installed on an early 2009 iMac.Any reason why your instructions shouldn't work on it? That didn't work either, so I then tried to just reboot without reinstalling, but now, even a straight reboot won't go back to her old Lion OS - it keeps wanting to do an internet install of El Capitain. That didn't work, so I next tried to use an El Capitain installer, which I already had on a USB flash drive.

She was having problems with strange things happening on her system, so I thought the best way to fix them was to reinstall Lion, which was what was currently running on her old iMac. I'm actually trying to help a neighbour with this problem, so it will be a couple of days before I can get to her home to try your instructions. If you want more information about that then ask. Your 2019 iMac can install Yosemite or El Capitan which are available as free downloads. If this works then when the OS is installed and booted up you can Open System Preferences> Date & Time

If Terminal returns an error saying sudo : command not found, then try again without sudo. Make sure WiFi is switched off, it can reset the date back to today.Įnter a new date, for example or just copy and paste Try this workaround, we are going to set the time and date on your mac to a date previous to the expiry date of the certificates.Ĭonnect your mac to your router via cable, not WiFiīoot to your Recovery HD, click on Utilities in the menubar select Terminal. This may be the problem you are experiencing. The certificates for several of Apples OS's expired in October 2019, Apple have been very poor at getting these updated on their Recovery Servers with valid certificates. If you want to try internet recovery follow this, You will e-mailed a redeem code which you use in the App Store (not the Apple Online Store).įrom macOS Sierra Apple stopped the Purchased section of the App Store showing previously downloaded

Mac OS X Lion is only available as a $20 from the Apple Online Store (not the App Store) when you purchase
