One or more folders in your mailbox have name conflicts with others or system reserved names.

Hi Chris, thanks for your response, I was on a Microsoft forum and found this thread, which I don't fully understand. I thought when it mentioned Apple mail, I had to make changes to the account on my i-Pad. I initially tried to rename the Junk Folder on my Hotmail account but it is greyed out.

To prevent this from happening involves changing some of the advanced settings for the account in the application you're using. How to do this will be different for each application and for each version of the application, which may be one of these:

• Apple Mail
• Mac Mail
• Gmail app on a tablet or smart phone
• Manufacturers' apps on Android devices, e.g. Samsung Email

You will have to consult the help documentation for the one you're using to find out how to match (or 'map') the Outlook.com folders to the ones in the application. There are too many variants for it to be possible to give them here. You may be able to get the correct instructions by asking

How do I map the Sent folder at Outlook.com to the sent items folder in [insert the name and version of your email application]?

Hi Chris, thanks again for your reply, the MS thread I added was misleading. I logged on my account on the Web Browser and found a sub folder called junk. I deleted this and the problem was resolved.