How to Prevent Guests Cannot Upload to a Shared Folder

When you share a folder in SharePoint or OneDrive with external users, those guests sometimes cannot upload files. This happens even when they can view or download the folder contents. The problem usually comes from incorrect sharing permissions or missing edit rights on the folder. This article explains the exact settings that control guest upload ability and how to fix them so external collaborators can add files.

Why Guests Cannot Upload Files to a Shared Folder

When you share a folder with a guest user, SharePoint generates a unique link. The link has a permission level that determines what the guest can do. If the link is set to “View” only, the guest can see files but cannot create, edit, or upload anything. This is the most common cause of the upload problem.

Another cause is the folder-level permission inheritance. If the folder inherits permissions from a parent library that restricts write access, guests will not be able to upload. For example, if the parent document library has “Read” permission for external users, every folder inside it also blocks uploads.

The site-level external sharing setting also matters. If sharing for the site is limited to “Existing guests” only, new external users cannot be invited. This prevents them from receiving upload permissions at all.

Steps to Allow Guests to Upload Files to a Shared Folder

1. Check the current share link permission
   Navigate to the shared folder in SharePoint or OneDrive. Select the folder and click the Share button. In the sharing dialog, look for the link type: “Anyone with the link”, “People in your organization”, or “Specific people”. Click the gear icon next to the link to open link settings. Make sure the Allow editing checkbox is checked. If it is unchecked, guests can only view and download files.
2. Update the link to allow editing
   If the checkbox is unchecked, check it and click Apply. Then send the updated link to the guest. The guest must use the new link to access the folder. Existing links with view-only permission will not allow uploads even after you change the folder permissions.
3. Grant Contribute permission on the folder
   If the link already allows editing but uploads still fail, you need to adjust folder-level permissions. Go to the folder, click the three dots (More actions), and select Manage access. Under the guest name, change the permission from “View” or “Read” to Contribute or Edit. Contribute permission allows users to add, edit, and delete files in that folder.
4. Stop permission inheritance if needed
   If the folder inherits permissions from the parent library, you must break inheritance to apply unique permissions. In the folder’s Manage access panel, click Advanced permissions settings. On the Permissions page, select Stop Inheriting Permissions. Then add the guest with Contribute or Edit permission. Note that breaking inheritance creates a separate permission set that you must manage manually.
5. Verify site-level external sharing
   If the site still blocks external uploads, check the site collection sharing settings. Go to SharePoint admin center, select Active sites, find your site, and click its name. In the Policies tab, look at External sharing. Set it to Anyone or New and existing guests for the upload feature to work. The “Anyone” option allows anonymous link sharing with editing rights. The “New and existing guests” option requires guests to sign in with a Microsoft account.
6. Resend the share invitation
   After you change permissions, the guest must receive a new invitation. Click Share on the folder again, enter the guest email, and set the permission to Can edit. Click Send. The guest receives an email with a link that includes the new permissions.

Common Mistakes When Sharing Folders with Guests

Guest receives a view-only link by mistake

When you share a folder using the quick Share button, SharePoint creates a link with the default permission for that site. The default is often “View” only. Always check the link settings before sending. If you already sent a view-only link, create a new link with edit permission and share it again. Do not rely on changing the folder permissions alone — the link itself controls access.

Folder inherits Read permission from parent library

If the document library has unique permissions that restrict external users to Read, every folder inside will also block uploads. You must break inheritance on the specific folder or change the library permission to allow edit for external users. Breaking inheritance is the cleaner approach because it limits the change to one folder.

Site external sharing is set to Existing guests only

This setting prevents new external users from being added. If you try to share a folder with someone who has never accessed the site, SharePoint will not send the invitation. Change the site sharing setting to New and existing guests or Anyone to allow new collaborators. Existing guests who already have access will continue to work.

Guest uses a personal Microsoft account instead of a work account

Some organizations require guests to authenticate with a work or school account. If a guest tries to use a personal account like @outlook.com or @gmail.com, upload may fail. Ask the guest to sign in with the email address that received the invitation. If the guest does not have a work account, the site must be set to Anyone sharing, which does not require sign-in.

Share Link Permission vs Folder Permission: Key Differences

Item	Share Link Permission	Folder Permission
Scope	Applies to the specific link only	Applies to all access to the folder
Control	Can be set when creating the link	Set in Manage access or advanced permissions
Guest upload	Requires “Allow editing” checked	Requires Contribute or Edit level
Inheritance	Independent of folder inheritance	May inherit from parent library
Re-sharing	Link can be forwarded without permission change	Permission stays with the user account

You now know how to prevent the “guests cannot upload” error by adjusting share link permissions and folder-level access. Start by checking the share link settings and ensure “Allow editing” is enabled. If that does not work, grant Contribute permission on the folder and verify site-level external sharing policies. For a long-term solution, use unique permissions on shared folders instead of relying on inherited settings.