Issue
- Sep 11, 2020 Click the Apple menu Restart. Once your Mac has booted up, connect your USB drive. Open Disk Utility. Select your USB drive in the left column, then click Erase.
- Just found a fix for this for my situation: I was re-installing the OS X on my daughter's 2006 MacBook to speed it up. After I erased the old HD and was trying to install the new OS (Lion, in this case), I was also met with the repeating 'This item is temporarily unavailable.
Use Apple Configurator 2 to “revive” your Mac. This process also requires a second Mac computer, plus a USB cable to connect both devices. With those materials in hand, use Apple’s guide to.
Installing Mac OS X on iMac's blank formatted hard drive. Installation runs for 5-10 minutes and then fails with following error:
An error occurred while preparing the installation. Try running this application again.
Tried installing OS X El Capitan (10.11) and OS X Sierra (10.12) - the same error occurs in both cases.
Resolution
Issue was resolved by fixing incorrect time on the iMac and then clearing NVRAM.
Fix incorrect time
- Boot from Mac OS X installation disk / USB.
- Go to Utilities > Terminal.
- Type date to check the current date and time.
- If it's incorrect, run following to fix the date and time: date mmddHHMMyyyy
Where: mm - month, dd - day, HH - hour, MM - minute, yyyy - year
Clear NVRAM
- Shut down the Mac
- Start the Mac and as soon as you hear startup chime press and hold keys Command + Option + P + R.
- Keep holding the keys until Mac reboots and you hear another startup chime.
iMac 21.5' (2009)
Mac OS X El Capitan (10.11)
Mac OS X Sierra (10.12)
Mac OS X El Capitan (10.11)
Mac OS X Sierra (10.12)
View the discussion thread.
Issue
Installing Mac OS X on iMac's blank formatted hard drive. Installation runs for 5-10 minutes and then fails with following error:
An error occurred while preparing the installation. Try running this application again.
Tried installing OS X El Capitan (10.11) and OS X Sierra (10.12) - the same error occurs in both cases.
Resolution
Issue was resolved by fixing incorrect time on the iMac and then clearing NVRAM.
Fix incorrect time
- Boot from Mac OS X installation disk / USB.
- Go to Utilities > Terminal.
- Type date to check the current date and time.
- If it's incorrect, run following to fix the date and time: date mmddHHMMyyyy
Where: mm - month, dd - day, HH - hour, MM - minute, yyyy - year
Clear NVRAM
Try Again (blackmambajesus) Mac Os Catalina
- Shut down the Mac
- Start the Mac and as soon as you hear startup chime press and hold keys Command + Option + P + R.
- Keep holding the keys until Mac reboots and you hear another startup chime.
iMac 21.5' (2009)
Mac OS X El Capitan (10.11)
Mac OS X Sierra (10.12)
Mac OS X El Capitan (10.11)
Mac OS X Sierra (10.12)
Try Again (blackmambajesus) Mac Os X
View the discussion thread.