MacBook Running Hot Suddenly

I now hear the fan and the top-left bottom gets very hot. Is this due to a faulty Mac OS X update that I recently applied?
Miss Elaine Eos wrote on :

In article isw-7AE67B.21325524062007@redacted.invalid, isw isw@redacted.invalid wrote:

In article 467e7949$0$24692$4c368faf@redacted.invalid, Dan dan@redacted.invalid wrote:

I have always used my MacBook on 'better battery life', and it has run with no fan noise or noticeable heat. But recently I now hear the fan and the top-left bottom gets very hot. Is this due to a faulty Mac OS X update that I recently applied?

Open up "Activity monitor" and see if you have a process that's stuck and using a lot of CPU. Firefox has done that to me, and a "normal" Force Quit won't clear it, because the stuck process is not visible to the "Force Quitter"; Activity Monitor can identify it and kill it dead, though.

For me, network activity seems to activate the "jet engines"...