Basha wrote:

I recently moved into my first house (year built 1993). After a week,
I noticed that the electric outlets in the garage not working along
with one outlet outside just adjacent to garage. I checked all the
GFCIs. I checked all the circuit breakers. They look ok.

Even if the breakers look ok, try switching them off-and-on.

I got onto
the attique and couldn't find where those outlets are feeding from.
The grage door opener and the light bulbs in garage are working fine.
They are fed from seperate line. Is there a way that I can
troubleshoot/find out where these outlets are feeding from?

Since I was alone and kept going up-and-down from the attic to the
basement and into-and-out of several rooms, it took me a few hours to
figure out the wiring in a house that I moved into. However, it depends
on how much of your wiring is visible and/or accessible.

Correlate the wiring with circuit breakers - if you know which circuit
breaker controls which outlet/receptacle, then start from there and
trace the wiring to other outlets and receptacles till you figure out
each circuit. If you do this one circuit at a time and draw it on a few
pieces of paper, you'll have complete understanding of the wiring in
your house, which will help in the long run.

--
Himanshu