[jrafter]

My 21" G4 iMac running 10.4.7 suddenly won't sleep on its own, even tho' I haven't changed energy saver options. Any ideas? Thanks in advance!

[JKT]

What software have you installed recently?

Google Video Player and Veoh will prevent your Mac from sleeping in my experience.

[jrafter]

Originally Posted by JKT

What software have you installed recently?

Nothing, except the 7.0.1 iTunes update.

[JKT]

In that case, try performing a power management unit reset (aka PMU, if that is the model iMac you have).

[jrafter]

I tried re-setting PRAM, but that didn't work. I was reluctant to open my iMac (even the base) to do the power management unit reset, so I thought I'd delete the powermanagement.plist first. That did the trick!

Thanks for pointing me to the appropriate Apple site.