There's been a number of reports Catalina boot-up issues on some older Macs after running the macOS upgrade. After the upgrade process, the affected Macs display a flashing ? on startup.
We felt it was important to share this information to help reduce the risk of more people getting stuck with a serious problem.
It's suspected that the EFI is corrupting, with the fix being a main Logic Board replacement, with no combination of keyboard commands is resolving the issues.
The Macs people have reported with this issue include:
- 2015 MacBook Pro
- Mid-2014 MacBook Pro
- Late-2013 MacBook Pro
- Mid-2012 MacBook Pro
- 2012 Mac mini
This isn't a definitive list of potentially "at risk" devices and so caution should be taken before considering an OS upgrade.
In many cases, these Macs will be classed as either "vintage" or "obsolete" by Apple (link here). If this is the case, replacement parts may not be an option.
Although the people affected seem to have been unlucky, this reinforces the Moof recommendation to take a cautious approach to macOS updates. If this were to affect a number of your organisation's Macs, it could be very costly to resolve.
Some example Apple discussion threads can be found here:
Threads can be found here: