These store key information for your Mac. Resetting the SMC and NVRAM is no panacea, but can transform an apparently dying Mac.
firmware
Coupled with FileVault’s whole disk encryption, this can stop others from accessing your data. But there are disadvantages too.
Keeping it up to date is important, but there is a slight twist (as ever).
Trying to install Ubuntu on my Boot Camp partition crashed my iMac, and it will not now boot from its install optical disk. How can I recover it?
After installing additional memory, my iMac keeps falling over, usually with a kernel panic. Is this a problem with Yosemite?
After an interrupted firmware update, my iMac refuses to start up. What can I do?
The Eclectic Light Company 