Microsoft Forms file upload for external users — what works

No. Microsoft's help page for the question type says file upload is only available when “Only people in my organization can respond” or “Specific people in my organization can respond” is selected. Both of those settings require respondents to sign in with a work or school account in your tenant. “Anyone can respond”, the only option that reaches customers, applicants or suppliers, does not require sign-in, and it is exactly the setting that switches file upload off.

Microsoft support has confirmed the same thing on its own Q&A forum. In an accepted answer from November 2025, a Microsoft support agent wrote that this is intentional, that there is currently no admin policy or setting that enables uploads from external or anonymous users, and recommended a file request link instead. We checked the official pages again on 28 September 2026 and nothing has changed.

It also means a personal Microsoft account (Outlook.com, Hotmail, Live) can't collect uploads at all. Microsoft says the two in-organization audience options are only available for Office 365 Education and Microsoft 365 business users, and file upload depends on one of them being selected.

The short reason is storage. Microsoft Forms doesn't keep uploaded files itself. It writes them into your Microsoft 365 storage: into the form author's OneDrive for work or school for a personal form, or into the document library of the Microsoft 365 group's SharePoint site for a group form. Microsoft's troubleshooting article lists the upload errors, and nearly all of them come from SharePoint or OneDrive sharing settings, not from Forms.

Letting an anonymous visitor write files into a company's SharePoint is a real security decision: malware, oversized files and data you're now responsible for. Microsoft's support answer frames the block as a security and compliance choice. Our reading is that tying every upload to a known account in your directory is what lets Microsoft keep uploads inside your tenant's existing permissions, retention and audit rules, which an anonymous upload would sidestep.

If the option is greyed out even for internal forms, the cause is different. Check the audience setting first, then the causes Microsoft lists: “People in your organization” sharing links disabled or expired on the OneDrive or SharePoint site, the Limited-access user permission lockdown mode feature, Information Barriers, or a form that was moved into a group after files had already been uploaded.

Where files land decides who can see them, so it's worth choosing on purpose.

Files go to the author's OneDrive for work or school, under Apps > Microsoft Forms > the form's name > a folder per question. Only the author has access by default. If the author leaves and their account is removed, Microsoft says account-related Forms data is deleted 30 days after the account is removed from Microsoft Entra ID, so plan a handover before relying on one person's OneDrive.

Files go to the group's SharePoint site, in the Documents library under Apps > Microsoft Forms. Everyone with access to that site can open them, which suits a team inbox for applications or reports. Microsoft also notes that when Information Barriers are enabled, personal forms can't use file upload at all, but a group form still can. Group forms don't change the external rule: an outsider still can't upload.

Two traps from Microsoft's documentation: if the SharePoint site moves to a different domain, existing upload questions stop working and must be recreated; and moving an individual form into a group can make new uploads fail because Forms still points at the previous owner's OneDrive.

Most “anyone can respond is greyed out” threads are really two separate problems, and only one of them has an admin fix.

If “Anyone can respond” itself is missing or disabled, the fix is in the Microsoft 365 admin center: Settings > Org settings > Services > Microsoft Forms > External sharing. It has four options, all on by default, and the one that matters is “Send a link to the form and collect responses”. With it unchecked, nobody in the tenant can collect responses from outside. Microsoft also notes that this option must stay on for Outlook polls to work.

If “Anyone can respond” works but the Upload file question is disabled, there's nothing to change. No admin-center checkbox, SharePoint sharing level or PowerShell setting adds file upload to an anonymous form. The SharePoint settings in Microsoft's troubleshooting guide (such as DisableCompanyWideSharingLinks) fix internal upload errors, not the external restriction.

Microsoft's Forms documentation doesn't say whether B2B guest accounts count as “people in my organization” for a form. Forum reports disagree, and we couldn't find an official statement, so treat it as unverified. If you plan to invite partners as guests just so they can upload, test the full flow with one guest account, including the upload itself, before you send the form to everyone.

Not always. If you collect a handful of files a month, the file request link is free, stays inside Microsoft 365, and your IT team already governs it. The cost is friction: respondents fill in the form, open a second page, upload, and remember to type a matching reference. Expect some people to forget one of the two steps.

Switching makes sense when the file is the point of the form: job applications with a CV, grant applications with a budget, supplier onboarding with certificates, or contest entries with a photo. There, a single submission that carries both answers and files saves you from matching them by hand every week.

Zunoform's file upload question works on every plan, including Free, and respondents don't need an account or a sign-in. Each question accepts 1 to 10 files, with a per-file cap of 10 MB on Free, 100 MB on Pro and 1 GB on Business, and files are stored with the response they belong to. Anonymous mode, if you turn it on, stops Zunoform storing IP address, user agent and similar metadata for that form.

Where it doesn't fit: if your policy says every file must live in your SharePoint tenant, a third-party form builder adds a data processor your IT or compliance team has to approve, and the file request workaround is the better choice. Zunoform also doesn't offer SSO, SOC 2 or HIPAA agreements. The Free plan is capped at 500 responses a month, where Microsoft Forms on a work account allows far more per form. Our Microsoft Forms alternative page compares the two in more detail.