w_tom writes:

Because important details are missing, then different answers are
provided; all correct because each is based upon different
assumptions.

Bob Shuman's and bz's answers assume a GFCI in the breaker box. As
correctly noted, a GFCI's white neutral wire must remains electrically
separated from all other neutral wires. And both black (hot) and
white (neutral) wires must be keep separate from other circuits so
that even milliamps cannot leak through a partially penetrated wire
insulation.

If GFCI is in the kitchen, then dodger741's answer is relevant.
That assumes the computer is somehow on the same circuit. Not clear
from your post which circuit has the GFCI.

Paul's questions about environment when tripping occurs is also
relevant.

And finally, if the microwave is generating too much common mode
noise, then common mode filtering in a computer (on a GFCI circuit)
could trip that GFCI. But that would have to be a massive common mode
noise generator - would definitively interfere with other radio
frequency equipment (AM radio, TV screen?).

On May 26, 10:24*pm, wrote:
Sometimes my microwave trips the other circuit that has our computers
on it, even though the appliance is on a different circuit at the far
end of the house. This happens maybe 1 out of 3 starts.

I've replaced the GFCI and it still trips; moved the microwave to a
third different circuit - same problem.

The microwave has been working normally for almost 5 years, but has
recently started making a buzzing sound on start up.

It might be worth taking the microwave and trying it on a circuit WITH
a GFCI (preferably, both the computer circuit and another one). It
should not trip.

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