Cannot share Office 365 with my sister

Hello Yves,

Welcome to Microsoft Q&A

I can see why that's so confusing. Getting told your sister is already registered but also that she can't install Office is a classic sign that the sharing invitation has gotten into a "stuck" state. It's a frustrating loop, but the good news is that it usually has a straightforward fix.

The most reliable way to solve this is to completely reset the sharing connection between your two accounts. This involves you removing her from your Microsoft Family group entirely and then sending a brand-new invitation to start fresh.

First, you need to completely remove your sister's account: Sign in your Microsoft Account's Family at Microsoft Family Safety > Find your sister's name/profile tile > Click the three dots (...) > choose "Remove from family group" > Confirm.

Next, just to be thorough, go to your Microsoft 365 Sharing page: Share subscription

If you still see her name listed under the "Other people" section, use the link next to her name to "Stop sharing".

Now that she's been completely removed, use the "Start sharing" button on that same page to send a brand-new invitation to her email address.

Once she receives the new email invitation, these steps are crucial to avoid the same problem:

1. Before clicking the link, ask her to sign out of any Microsoft accounts she might be logged into in her web browser.
2. Now, she can click the "Accept" link in the new invitation email you sent.
3. She will be prompted to sign in. She must sign in with the exact same Microsoft account email address to which you sent the invitation.
4. After accepting, she should be able to go to her own Microsoft account page and see the option to install Office on her new PC.

Please let me know if it helps.

Best regards,

Alex | Microsoft Q&A Support Specialist