Upgrade from mountain lion to mojave went wrong

Silver78

macrumors 6502
Original poster
Aug 24, 2013
365
95
Denmark
i did a complete reset of my mac and after it worked. Then i went and downloaded mojave and follow install instructions.
Now the mac write system could not be installed and only option is to press restart.
After restart it wants me to select system to start up on mac but show no options for system?!
Anyone know what i should do now?
 

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LuisN

macrumors regular
Mar 30, 2013
205
194
Torres Vedras, Portugal
i did a complete reset of my mac and after it worked. Then i went and downloaded mojave and follow install instructions.
Now the mac write system could not be installed and only option is to press restart.
After restart it wants me to select system to start up on mac but show no options for system?!
Anyone know what i should do now?
You MUST install High Sierra before going into Mojave so that your Mac upgrades its rom to support APFS which is mandatory to install Mojave. That’s why your computer can’t see any disk to install into
 

chrfr

macrumors G3
Jul 11, 2009
8,210
2,535
You MUST install High Sierra before going into Mojave
That is not the case.
[doublepost=1562523964][/doublepost]
i did a complete reset of my mac and after it worked. Then i went and downloaded mojave and follow install instructions.
Now the mac write system could not be installed and only option is to press restart.
After restart it wants me to select system to start up on mac but show no options for system?!
Anyone know what i should do now?
What model computer do you have?
 

LuisN

macrumors regular
Mar 30, 2013
205
194
Torres Vedras, Portugal
That is not the case.
[doublepost=1562523964][/doublepost]
What model computer do you have?
It is, he has a MBP 2012 AFAIK, so he can't go directly from anything prior to high Sierra to Mojave because it won't apply the required EFI update. I may be mistaken though...
 

chrfr

macrumors G3
Jul 11, 2009
8,210
2,535
It is, he has a MBP 2012 AFAIK, so he can't go directly from anything prior to high Sierra to Mojave because it won't apply the required EFI update. I may be mistaken though...
You're indeed mistaken. The required firmware update is applied as part of the Mojave installation process. The only exception to this is the 2010/2012 Mac Pro, which does require High Sierra to be installed first.
 

seabreeze56

macrumors member
Dec 4, 2016
42
3
Mine is a mid 2012 (non retina) and I was running on high sierra. I just installed Mojave and it's working great. Call Apple if you haven't already and ask them if you can go from mountain lion directly to Mojave. I was starting to have issues on HS. That's when I decided that my last ditch effort was to upgrade and it seemed to have fixed everything. I did call apple to make sure that it was ok (even tho I read it was) to go to Mojave on this "older" laptop without retina. And they said, YES - do it. And it worked out perfectly so far.