You can make a difference in the Apple Support Community!
When you sign up with your Apple Account, you can provide valuable feedback to other community members by upvoting helpful replies and User Tips.
When you sign up with your Apple Account, you can provide valuable feedback to other community members by upvoting helpful replies and User Tips.
Hi,
After upgrading from macOS Sierra 10.12.6 to macOS High Sierra, I get a prohibitory sign at startup. I recently upgraded to Transend 1TB SSD about 6 months ago. I have never had this issue before. I have tried booting with CMD + R and repairing my SSD which does so successfully but that doesn't seem to help. Any help to a permanent fix would be greatly appreciated.
MacBook Pro 15-inch Late 2011
TIA
MacBook Pro, macOS Sierra (10.12.6)
I also had this problem - on a 2016 MBP with touchbar. Not only did I have this problem after an upgrade, but about a week after doing a fresh install of High Sierra on this machine, the same thing happened again.
I took the machine to the genius bar and they confirmed the filesystem and hardware were performing normally. Prohibitory symbol remained and would occasionally boot-up after going into recovery mode. But safe mode never helped. This leads me to believe there is something wrong with APFS, which is mandatory for SSD's (something we both have in common). In my case, I choose to use APFS (Encrypted).
When doing the upgrade, the recovery mode to install a fresh macOS is also updated, so there's no way to go back unless you have the media for an older OS or go to the genius bar - they can boot virtually any macOS version from across their network.
The genius bar ended up performing a fresh install of Sierra (10.12.6) on this machine and it's been fine ever since. I'll be waiting for 10.13.2 or 10.13.3 before I even think about upgrading this machine again. I don't think APFS has been tested all that well and the tools that can potentially find issues with it, don't seem to work that well - since everything reported back as being fine, when in reality it wasn't.
I also had this problem - on a 2016 MBP with touchbar. Not only did I have this problem after an upgrade, but about a week after doing a fresh install of High Sierra on this machine, the same thing happened again.
I took the machine to the genius bar and they confirmed the filesystem and hardware were performing normally. Prohibitory symbol remained and would occasionally boot-up after going into recovery mode. But safe mode never helped. This leads me to believe there is something wrong with APFS, which is mandatory for SSD's (something we both have in common). In my case, I choose to use APFS (Encrypted).
When doing the upgrade, the recovery mode to install a fresh macOS is also updated, so there's no way to go back unless you have the media for an older OS or go to the genius bar - they can boot virtually any macOS version from across their network.
The genius bar ended up performing a fresh install of Sierra (10.12.6) on this machine and it's been fine ever since. I'll be waiting for 10.13.2 or 10.13.3 before I even think about upgrading this machine again. I don't think APFS has been tested all that well and the tools that can potentially find issues with it, don't seem to work that well - since everything reported back as being fine, when in reality it wasn't.
Some aspect of the System files in corrupted.
https://support.apple.com/en-us/HT204156
I would fall back to your last macOS and try again
There is a way...
Thanks for the quick reply…
I have up to the minute backup…
I did an upgrad and restore twice… with no success…!!
”Some aspect of the System files in corrupted” is there any way to find which files…?
TIA
So from what I’m reading only way to fix this is the Genius Bar?
I have seen this problem on machines with and without SSDs. In all cases reinstalling High Sierra has adequately address the problem.
Prohibitory sign on startup with macOS High Sierra
