What file storage should I use if I need external partner access with tight permissions?

If you need external partner access with tight permissions, the safest choice is usually cloud file storage with granular sharing controls and audit logs rather than a traditional file server.

Best options

• Microsoft SharePoint / OneDrive (with guest access)

  • Good for organizations already using Microsoft 365
  • Strong permission control at site, folder, and file level
  • Supports guest invitations, expiration, MFA, and audit logs

• Google Drive / Shared Drives (with external sharing controls)

  • Good if your organization uses Google Workspace
  • Easy partner collaboration
  • Can restrict download, print, copy, and sharing on some plans

• Box

  • Often considered one of the strongest for external collaboration
  • Fine-grained permissions, link controls, watermarking, expiration, and detailed audit trails
  • Frequently used for regulated or partner-heavy workflows

What to look for

For tight permissions, prioritize:

• Granular access control: folder/file-specific permissions
• Guest/external identity support: invited users instead of public links
• Link expiration and password protection
• Read-only / no-download controls
• MFA / conditional access
• Audit logging
• Versioning and revocation
• Data loss prevention (DLP) if sensitive data is involved

What to avoid

• Simple network shares exposed over VPN
• Public file links without expiration
• Consumer-grade storage for sensitive partner files

Practical recommendation

• If you already use Microsoft 365: start with SharePoint
• If you need the strongest external collaboration controls: consider Box
• If you’re in Google Workspace: use Shared Drives with external sharing restrictions

If you want, I can recommend the best option based on your environment: Microsoft 365, Google Workspace, AWS/Azure, or on-premises.