Tools and Account Setting, in Default Identity section, fill in your name in "Your name"

Thanks, I had my name in there already. It doesn't change a thing.

Some info here - this might explain your issue but it is a Microsoft thing not a Thunderbird bug.

• https://support.microsoft.com/en-gb/office/outlook-com-email-account-appears-as-outlook-long-series-of-letters-and-numbers-outlook-com-in-outlook-for-windows-90ed7938-7f21-4cb5-a69d-a3b79ea4eafd

In the Microsoft account, all email addresses are considered 'alias' and you can set up one as 'primary'. Whatever email address is set up as 'primary' must be used for the smtp when sending from a third party email client such as Thunderbird.

Micosoft say: This issue can occur when you register a 3rd party email address (e.g., an email address that is not Outlook.com or Hotmail.com) for your Microsoft Account and don't use Outlook.com for sending and receiving email.

I have seen this before - https://support.mozilla.org/en-US/questions/1465652#answer-1680651 That user discovered via their Microsoft account webmail that the email address really did have some weird numbers. They included some images showing their issue.

Thanks for the response and direction. Support Microsoft states this: 1. Close Outlook 2. Use Windows Key + R then type “outlook /profiles” (omitting the quotes) in the Run window and hit “OK” Note: There is a space between outlook and the forward slash (/) 3. In the launched “Choose Profile” box, select Options > New 4. Type a new, unique profile name and select OK 5. Choose Advanced options > Let me set up my account manually. 6. Enter your account password, then choose Connect. 7. If setup fails, select Change Account Settings. Update the account information with the one you received from your email provider or from the POP and IMAP server name reference topic. Choose Connect then then select Done. 8. In the Choose Profile window, select Set as default profile and select OK.

Sorry if this is a stupid question but in which application would I undertake step 2 on my mac?

Those instructions sound like Microsoft is assuming you use 'Outlook' email client. So are not relevant.

In the Microsoft account accessed using a browser - Do you have any other Microsoft email address such as name@outlook.com ?

I would advise you use the info at link under:

'ALTERNATIVE WORKAROUND'

Switch your alias to an Outlook.com or Hotmail.com account. Note: If you do not have another alias, select the link on the page to create one. Choose Add email and a new alias and then choose the option Create a new email address and add it as an alias.

That would mean creating an outlook email address (assuming you not have one) and then setting it up as 'primary' alias. Then you may need to alter the smtp to send using the outlook.com email address. You would also want recipients to reply to your original email address - the one migrated to office server - so in Account SEttings > select name of account and in the 'Reply-to Address' insert the email address of migrated account. That means even if sending using the outlook.com email address, you should get replies back into the correct account.

Additional info that enforces what I found and offers info:

• https://learn.microsoft.com/en-us/answers/questions/4707767/my-account-has-this-weird-address-outlook-(a-few-n
• https://learn.microsoft.com/en-us/answers/questions/4609658/outlook-email-is-random-numbers-and-letters-how-do

When logging in to 'outlook.com' webmail account you can send from any of your 'alias' email address. But when using third party email clients eg: Thunderbird, Microsoft only lets you send using whatever is set up as the 'primary' alias.

Hi Toad Hall, Many thanks for all your advise. I had actually used outlook with my email account and I have now set up another account as an alias but I have no clue what to do from here. I am just not savvy with IT stuff enough to deal with this while the problem of the wrong name showing up remains which is very irritating to the recipients of my emails. Do you offer paid help to solve this issue logging into my Mac? I am happy to pay someone rather than ruining my nerves any further. Thanks!

re :I have now set up another account as an alias

I presume this is a name@outlook.com type of email address. Have you set it up as the 'primary' alias ? If no then please set up as 'primary' - you can only do that in the microsoft account webmail page.