Learn English – Difference between “to occur” and “to happen”

differenceword-usage

From time to time I have an error in a computer system.

What is better to say:

  • The error happened again yesterday.
  • The error occurred again yesterday.

Is there a semantic difference between the two sentences?

Does one of the two carry a kind of surprise? I want to express, it is not surprising, it just happened again.

Best Answer

It's an interesting question. As @Mistu4u mentioned, the formal definitions of both words are similar.
There are some differences, however:

Happen — something random to take place;
Occur — something to become observable; in a certain moment; an event or a process;

The difference is even more evident if you notice that occur is relative to current as they both came from Latin currere "to run".

So, I would use occur in the following contexts:

...and happen in the following contexts:

  • Informal context;
  • Rough time or place;
  • Random events, usually without being planned;

As usual, you can step off these recommendations if you need to convey your attitude about what you are speaking about.