We need to share a folder containing several Excel files with someone outside our organization. Sharing works normally with our accountant, but this particular user's company does not provide Microsoft software such as Office or Outlook and apparently uses a free office suite instead.
I tried adding them as a guest, but they said they could not complete the validation. I also tried sharing the folder specifically with their email address, but they still could not get through the MFA and authentication steps. Our software provider's support team has not been able to resolve it either.
We are now considering buying Microsoft software for this person, but I am unsure what would actually be needed. Would a SharePoint Plan 1 license be enough? Could they access the folder and open or edit the Excel files using their existing office suite? Does browser access require a Microsoft account or Microsoft license, or could they simply use an authenticator app or email verification?
What is the simplest secure way to give this external user access? My employer expects me to find a solution, even though their own company would normally be responsible for providing the necessary software.
4 Answers
Your current sharing choices suggest that anonymous links are disabled at the tenant or site level. That is generally a good security decision, so I would not change it just to avoid authentication. Instead, keep using specific-person sharing and configure guest email verification or invite the person as a contractor-style guest. If they still cannot complete the flow, check the invitation redemption status, their browser, blocked third-party cookies, and any authentication policies affecting external users.
They do not necessarily need Microsoft software or an existing Microsoft account to be added as a guest. Add the person using their work email address and use email one-time passcodes for verification. They should receive a code by email when signing in, which avoids requiring Outlook or another Microsoft application. Check that guest access and email OTP are enabled in your tenant, and verify that conditional access is using the normal MFA requirement rather than an authentication-strength policy that the guest cannot satisfy.
That is useful to know. I had assumed the failed validation meant they needed a Microsoft account, but it sounds like the sign-in and the Office software are separate issues.
Buying SharePoint Plan 1 may not solve the underlying problem. It controls access to SharePoint, but it does not guarantee that the other company’s office suite will open Excel files correctly or that the user can edit every workbook in the browser. If browser editing is not sufficient, the practical alternatives are to have their company provide a compatible spreadsheet application, export simpler files to a format their suite supports, or use an approved external file-sharing workflow. Avoid weakening MFA just to make the sharing link work.
An Entra ID guest account can usually access the shared SharePoint folder through a browser, and the Excel files may be viewable or editable in Excel for the web depending on your tenant’s sharing and licensing settings. The external user does not automatically need a full employee-style Microsoft 365 license just to be a guest. Test the exact permissions with a sample file before buying anything.
The site only offers company members, existing access, or specific people, and the Anyone option is greyed out. So anonymous sharing appears to be disabled centrally.