In short: To send large files securely, don’t use email: use a secure file transfer solution with recipient verification, an expiry date, revocable access and an audit trail. By default, email stops at around 25 to 35 MB per message. With Msafe you share files up to 1 TB as standard (larger files on request), including straight from Outlook, with data hosting in the Netherlands and logging of every transfer. For occasional use, TransferOne by Msafe lets you share up to 25 GB per transfer for free.
Sending a file of a few gigabytes is no longer a technical problem. The real question is what happens next: does only the right recipient get access, does that access expire on time and can you show afterwards what happened to the file?
With a secure file sharing solution you can exchange large files in a controlled way, without email attachments, unmanaged public links or USB sticks. Msafe supports files up to 1 TB as standard. Larger files are available on request.
This article covers how to send large files securely in practice: the limits of email, the risks involved and how to keep convenience from coming at the expense of information security.
What does sending large files securely mean?
Sending securely means more than encrypting a file during transfer. An organisation also needs to keep control over:
- the identity of the recipient;
- who may open or download the file;
- how long the file remains available;
- revoking access that is still active;
- recording send, access and download activity;
- where the data is stored;
- the policy employees must follow when sharing files externally.
File size is therefore only one part of the picture. It is mainly the combination of confidentiality, access management and demonstrability that determines whether a transfer is handled responsibly. What this means for your organisation more broadly is explained in secure file sharing for organisations.
How large can a file be? Email limits versus Msafe
Most organisations first run into the maximum size of an email attachment. These are the standard limits:
| Channel | Maximum size |
|---|---|
| Microsoft 365 / Exchange Online (default) | 35 MB to send, 36 MB to receive per message; administrators can raise this to a maximum of 150 MB |
| Outlook for iOS and Android | 33 MB per message |
| Gmail (personal account) | 25 MB of attachments; above that, Gmail inserts a Google Drive link |
| TransferOne by Msafe (free) | 25 GB per transfer, available for 7 days |
| Msafe Secure File Transfer | Files up to 1 TB as standard, larger files on request; unlimited number of transfers |
Sources: Microsoft, Exchange Online limits; Google, Gmail Help; Msafe pricing (October 2026). Note: messages that leave Microsoft datacenters grow by about 33% due to encoding, so the effective limit is lower.
Why email is not the way to send large files securely
Email was designed for communication, not for the controlled transfer of large or sensitive datasets. In addition, email platforms, receiving servers and organisations apply different limits to messages and attachments. A message that leaves your outbox can still be rejected by the recipient’s server.
As a result, employees sometimes look for a quick workaround, such as a personal cloud account, a public transfer service or a USB stick. The organisation may then lose sight of where information is stored, who has access and how long that access remains active. Read also why you should avoid emailing sensitive documents.
A single wrong address picked by autocomplete can lead directly to a data breach via email. Mistakes like that are human, but a sent email attachment usually cannot be retrieved. Read how to prevent data breaches due to human error.
With secure file sharing you usually don’t send a file as an attachment, but grant controlled access to a secure environment. This allows you to attach conditions to access and revoke it again, as long as the file has not been stored locally.
OneDrive and SharePoint: collaboration or file transfer?
Microsoft 365 offers extensive options for storage, collaboration and external access. According to Microsoft’s external sharing documentation, the final level of security depends partly on tenant settings, the type of sharing link and the access rights users select.
OneDrive and SharePoint are particularly strong when people work together on documents over a longer period. For a one-off, controlled transfer to an external recipient, a specialised secure file transfer solution can be clearer.
So the question is not which solution is better in general. The use case determines which solution fits best:
- Collaborating on documents: OneDrive, SharePoint or Teams.
- Controlled file transfer: secure file transfer.
- Collecting sensitive documents from external parties: a secure upload environment.
- Demonstrable delivery and access: a solution with detailed logging.
Read also the comparison between SharePoint and Secure File Transfer. Considering a consumer service? Msafe as a business alternative to WeTransfer helps you weigh the options.
What are the risks of sharing files externally?
Unauthorised access
A public link can be forwarded to someone the file was not intended for. Identity verification, for example with a PIN code or two-factor authentication, reduces that risk.
Excessive availability
A sharing link you sent in March often still works in September. With an automatic expiry date, access closes by itself, even when nobody remembers it.
Insufficient visibility
Without logging it is difficult to determine whether a recipient has opened or downloaded the file. This complicates audits, incident investigation and accountability.
Use of unapproved services
When the approved solution is too complicated, employees are quicker to choose their own tools. A secure way of working must therefore also be simple enough for everyday use.
Unwanted file types
Not every file belongs on an external sharing route. Executable files, for example, can pose a security risk. With central policy you decide which file types may not be shared.
Loss of control after downloading
Access to a file can be revoked within a platform. A local copy that has already been downloaded usually cannot be deleted remotely. Restrict downloading where necessary and only share the data the recipient actually needs.
Send large files securely in 5 steps
Whether it is a 4 GB construction drawing or a 2 MB personnel file, the steps to send files or documents securely are always the same. This is how you do it.
- Choose a business solution. Don’t use a regular attachment or a free transfer link, but a service where you know where files are stored and who can access them.
- Add the recipient by email address. A personal invitation is safer than a public link anyone can forward.
- Have the recipient verify themselves. With a PIN code, 2FA or a one-time code by phone, you know the right person opens the file.
- Set an expiry date. A week is more than enough for most transfers.
- Check delivery. See in the log whether the file has been downloaded and revoke access if needed.
Working in Outlook? With the Msafe Outlook add-in you send the file from your own mail window through Msafe, with the same verification, expiry date and logging. Nobody has to learn a new way of working.
Strong authentication is important here. The NIST Digital Identity Guidelines explain why a username and password alone often provide insufficient protection. For a practical application, read also about the importance of 2FA.
How does Msafe support large file transfers?
Msafe Secure File Transfer is built for organisations that send large files securely to clients, suppliers and partners, and want to stay in control of who receives what.
Depending on the configuration and plan, Msafe offers among other things:
- files encrypted with AES-256;
- file sharing up to 1 TB as standard, larger files on request;
- an unlimited number of file transfers;
- verification of external recipients with a PIN code or 2FA;
- Easy Download: recipients download without an account, after a one-time verification by phone number;
- configurable access rights and expiry dates;
- the option to revoke access that is still active;
- policy rules that determine which file types may not be shared (since Msafe 2.5);
- logging of send, access and download activity;
- Single Sign-On and SCIM for central user management;
- an Outlook add-in (the Msafe Connector);
- an API for automated processes;
- the application in six languages: Dutch, English, German, French, Spanish and Italian;
- data hosting in the Netherlands and ISO/IEC 27001:2022 certification.
“Unlimited sharing” means that the number of transfers is not restricted. Files up to 1 TB are supported as standard. Larger files are available on request. See pricing and plans for an overview.
Need to send a large file only occasionally, without central management? With TransferOne by Msafe you share up to 25 GB per transfer for free, without an account and with hosting in the Netherlands.
Sharing large files in practice
At Dutch Railways (NS), employees use Msafe to share large and confidential files with external parties, from certificates and camera footage to heavy construction drawings. Suppliers also use Msafe to share confidential files with NS. Wim Brummel, Product Manager Workplace Services at NS: “It is simply a good product. It works and takes little time.”
At PAL-V, developer of the PAL-V Liberty, it involves construction drawings, CAD models and test results containing intellectual property. PAL-V moved from freely available transfer services to Msafe Enterprise.
Working with BIM models and CAD drawings in construction or industry? Read securely sharing large files in construction and industry.
Secure sharing from Outlook
Secure file sharing doesn’t have to mean a new way of working. With the Msafe Connector for Outlook, you send files through Msafe from your own mail window instead of as a regular attachment.
Employees keep working in the mail environment they know, while Msafe secures and records the transfer. That makes working securely the easiest route instead of an extra step. Read more about the Msafe Connector for Outlook.
Does secure file sharing make an organisation compliant?
A technical solution does not automatically make an organisation compliant. Compliance depends on policy, processes, responsibilities, configuration and the actual use of the solution.
Secure file sharing can, however, help to apply and demonstrate appropriate security measures. Think of encryption, access management, retention periods and logging.
These measures align with the security obligations in Article 32 of the GDPR. The European NIS2 Directive, implemented in the Netherlands through the Cybersecurity Act (Cyberbeveiligingswet) that has been in force since 15 August 2026, also requires risk management and appropriate security measures. Read what this means for file sharing in the Cybersecurity Act and admissibility of evidence.
The exact measures depend on your organisation’s risks, data and legal obligations. The management guide Control over secure file sharing offers a practical four-step model: policy, access, use and evidence.
A practical checklist for IT and security teams
When choosing a solution, assess at least the following:
- What is the maximum file size per transfer?
- Where are files and metadata stored?
- Is data encrypted in transit and at rest?
- Can recipients be verified with 2FA or a PIN code?
- Can expiry dates be made mandatory?
- Can access be revoked after sending?
- Are opening, downloading and other activities logged?
- Can administrators enforce central policy, including for file types?
- Are SSO, SCIM and API integrations supported?
- Who owns the supplier and which jurisdiction applies? Read also data sovereignty in 2026.
- Is the solution simple enough to prevent uncontrolled alternatives?
Frequently asked questions
How can I send a large file securely?
Use a business secure file transfer solution in which the file is stored and sent encrypted. Then configure recipient verification, an expiry date, appropriate download rights and logging.
How do I send a file securely from Outlook?
With the Msafe Outlook add-in you send files from your own mail window through Msafe. The recipient verifies themselves, access expires on the date you set and every download is logged. You are also no longer stuck with the 35 MB attachment limit.
What is the attachment size limit in Outlook?
In Microsoft 365 the default limit is 35 MB per sent message, including attachments. Administrators can raise this to a maximum of 150 MB, but the receiving server may apply a lower limit. For larger files, use a secure file transfer solution.
What is the maximum file size supported by Msafe?
Msafe supports files up to 1 TB as standard. If you work with even larger files, that is possible on request.
Can I send a large file securely for free, also as an individual?
Yes. With TransferOne by Msafe you share up to 25 GB per transfer for free, encrypted and hosted in the Netherlands. You don’t need an account and free transfers are available for 7 days. For central management, logging and policy, choose Msafe Secure File Transfer.
Is WeTransfer safe for confidential files?
WeTransfer is built for convenience. For confidential files, organisations often miss central control: recipient verification, mandatory expiry dates, revoking access and an audit log you can show during an audit. The comparison Msafe as a business alternative to WeTransfer lists the differences.
Is it safe to send large files by email?
Email can be suitable for regular communication and smaller, non-sensitive documents. For large or confidential files, the desired control over recipients, expiry dates, revocation and audit information is often missing.
Are OneDrive and SharePoint unsafe?
No. Microsoft 365 offers extensive security and collaboration features. A specialised secure file transfer solution can, however, be a better fit for one-off, controlled external transfers and central audit requirements.
Does an external recipient need an Msafe account?
No. With Easy Download, an external recipient downloads files after a one-time verification by phone number, without an account or password. Per share you decide whether a recipient gets an account or uses Easy Download.
Can I retrieve a file after sending it?
You can revoke active access to a file as long as the file remains within the secure environment. A copy the recipient has already downloaded usually cannot be deleted remotely.
Send large files securely with Msafe
Sending large files securely is not about storage space, but about control: who receives the file, how long can they access it and can you prove that later?
With Msafe you combine that control with a way of working that employees and external recipients understand without explanation. You exchange large and sensitive files quickly, while your organisation keeps sight of every transfer.
Book a no-obligation demo or request a proof of concept and test Msafe with your own large files.
