HMRC has sent me a notice to file but I don't think I need to. What do I do?

Don't ignore it. A notice to file is a legal requirement, and if you miss the deadline the automatic £100 penalty applies even if you end up owing nothing. Contact HMRC and ask them to withdraw the notice — you can do this by phone or post, explaining why you don't believe you need to file. HMRC will confirm in writing if they agree to remove it. Until you get that confirmation, the return is still due. If you're unsure how to approach it, get in touch via live chat and we can advise.