Unmodified opinion
In one sentenceAn opinion the auditor gives when satisfied that the financial statements are fairly presented in all material respects. It is also called a clean opinion.
Simply put
A clean opinion is the best outcome of an audit: it means the auditor found no material misstatements, or that they were corrected before the report was issued.
It does not mean every figure is correct to the last halala, because the audit relies on samples and materiality.
Example
At a factory, the auditor found an error in the depreciation of one machine. Management corrected it before the statements were issued, so the report was issued with a clean opinion.
Don't confuse it with
Qualified opinionA clean opinion has no exception, while a qualified opinion excludes a specific item with a material misstatement or a lack of evidence.