May be you are working on a processor intensive task and there is extremely low disk space. Or, you have a USB Device connected - [this Happened to me] - most probably an external Hard Disk and you deleted some files from it but did not clear the trash. After ejecting the HDD, and connecting it again; then emptying the trash - gave me the same message telling me to hold the power button and restart my mac. Update: Yes, even interchanging the RAM in the slots may work. And the suggested solution is also an easy test.
try running your mac in Safe mode - pressing "Shift" key while booting up. It will reset all the Kernel Extensions (kexts) and may be the cause of the problem too.
DJ: I just removed a half-broken SD Card from the slot using this guide. It requires a pin or some fine pitch tweezers. You will have to get to the last step of this guide to get the micro SD assembly removed from your camera. Then, there is a metal tab (hook shaped) protruding from the side of the micro SD connector you have to gently pull it out of the way (from outside the micro SD connector). Then, you can insert a safety-pin or tweezers from the outside (right side of the connector) and pull out the broken card. Sounds confusing but cannot upload images here.
Also, note that if your card is locked inside the connector and you cannot remove it, you will have to eject it first from the slot to get it out a few mm.
[WARNING!!! - Follow at your own risk] Insert a new SD card and try to gently push the broken SD card inside. What it will do is unlock the broken card and eject it out a few mm.
DJ: I just removed a half-broken SD Card from the slot using this guide. It requires a pin or some fine pitch tweezers. You will have to get to the last step of this guide to get the micro SD assembly removed from your camera. Then, there is a metal tab (hook shaped) protruding from the side of the micro SD connector you have to gently pull it out of the way (from outside the micro SD connector). Then, you can insert a safety-pin or tweezers from the outside (right side of the connector) and pull out the broken card. Sounds confusing but cannot upload images here.
Also, note that if your card is locked inside the connector and you cannot remove it, you will have to eject it first from the slot to get it out a few mm.
[WARNING!!! - Follow at your own risk] Insert a new SD card and try to gently push the broken SD card inside. What it will do is unlock the broken card and eject it out a few mm.