Often suggests a result that wasn't expected and might be harmful or problematic. Their new policy had several unintended negative impacts on the employees.
Pro Tip 2/3
Impression Errors
Using 'unintended' can indicate you didn't mean to give a certain impression or message. His tone conveyed an unintended sense of urgency that confused us.
Pro Tip 3/3
Non-deliberate Action
Emphasizes actions done without intent or awareness that they would happen. The damage was unintended, as I had no idea my words could be so hurtful.