EDIT: Resposta atualizada para refletir o desenvolvimento trimforce da Apple: veja aqui
Aparar kext é alterado em Yosemite. Isso não é relevante se você estiver usando um SSD instalado pela Apple. Se você estiver usando um SSD DIY, o suporte ao Trim será complicado no Yosemite, devido às recentes modificações no gerenciamento de segurança do kext que afetam o suporte ao Trim. Saiba mais sobre o Trim Enabler para Mac .
About Trim in Yosemite In OS X 10.10 (Yosemite),
Apple has introduced a new security requirement called kext signing. (A kext is a kernel extension, or a driver, in Mac OS X)
Kext signing basically works by checking if all the drivers in the system are unaltered by a third party, or approved by Apple. If they have been modified, Yosemite will no longer load the driver. This is a means of enforcing security, but also a way for Apple to control what hardware that third party developers can release OS X support for.
Since Trim Enabler works by unlocking the Trim driver for 3rd party SSD’s, this security setting prevents Trim Enabler to enable Trim on Yosemite.
To continue to use Trim Enabler and continue to get Trim for your third party SSD, you first need to disable the kext signing security setting.
It is important to note that the kext-signing setting is global, if you disable it you should be careful to only install system drivers from sources that you trust.
Algumas unidades funcionam sem Trim ativado: ZDNet em problemas com o Trim em Yosemite .
Boa sorte!