Are 改正 and 纠正 interchangeable? Both 改正 and 纠正 mean "to correct" or "to make right." 

What is the difference between these words? Do they have different connotations? Are both words acceptable in sentences like the following?


  错误一经发现，就应立即（改正、纠正）。
  Mistakes should be corrected as soon as they are discovered.
The grammar is the same for both, but 纠正 often has a stronger meaning. It is often used when a lot needs to be changed or the errors are more serious, and 改正 is often for smaller changes, when not that much needs to be changed. Also 改正 is more used when you want to correct your own errors, instead of other people's errors.

The are both typically used for 缺点 (shortcomings) and 错误 (errors).

In 《现代汉语规范词典》 I found this: "改正"是主体的自觉行为；"纠正"可以含有强制意味

I think 纠正 is slightly better in your sentence, since these errors need to be immediately corrected, they are probably a little bit more serious.