This article from the Apple Knowledge Base: Reset the System Management Controller (SMC) on your Mac

describes very well which kinds of events are symptoms which might be related to an SMC in need of a reset. But the relationship isn't clearly established.

Is there any simple method to diagnose clearly the SMC state:

  • is it OK?
  • does it need a reset?

Something like (for NVRAM):

nvram -p


nvram -p | diff /etc/nvram.backup -

Your best bet is to go through Apple's diagnotic utilities, but be prepared for it to tell you everything is fine.

Put you machine on a flat stable surface and plug it in. Perform a restart or a power on and immediately hold down the 'd' key (d for diagnostics). It should at least test your power adapter which is goverened by the SMC chip.

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