Data Loss Prevention (DLP): how to stop sensitive data leaving your business
Data Loss Prevention combines policies and technology to stop sensitive information leaving your organisation, by accident or on purpose.
Updated October 2026 · 5 min read
Securing sensitive business information is now a basic requirement. Data Loss Prevention (DLP) brings together tools, policies and technology to protect important data from leaks, breaches and unauthorised access.
What is Data Loss Prevention?
DLP solutions find sensitive information, such as customer records, financial data or trade secrets, and apply rules to how it can be used. A rule might block a file containing card numbers from being emailed externally, or warn a user before they upload confidential documents to a personal cloud account.
Where DLP protects your data
- Email: stops sensitive data being sent to the wrong recipients.
- Endpoints: controls copying to USB drives, printing and screen capture.
- Cloud apps: monitors sharing in services such as Microsoft 365 and other SaaS tools.
- Network: inspects data leaving the organisation.
Why DLP matters
- Protects intellectual property: trade secrets and new ideas stay confidential.
- Supports compliance: helps meet data protection and industry regulations and avoid penalties.
- Preserves customer trust: prevents exposure of customer information.
- Reduces financial loss: avoids the cost of breaches and incident response.
- Keeps the business running: prevents disruption caused by data loss incidents.
How to roll out DLP successfully
- Classify your data: decide what counts as sensitive and where it lives.
- Monitor first: run policies in audit mode to see how data actually moves.
- Tune policies: reduce false positives before you block anything.
- Enforce in stages: start with the highest-risk data and channels.
- Train your people: explain the rules and why they exist.
Frequently asked questions
Does Microsoft 365 include DLP?
Microsoft 365 includes DLP capabilities in Microsoft Purview, depending on your licence. Business Premium and E3/E5 plans include different levels of protection.
Will DLP slow down our staff?
Well-tuned policies stay in the background. Starting in monitoring mode helps avoid blocking legitimate work.
Is DLP only for large enterprises?
No. Any organisation that handles customer, financial or confidential data can benefit, and cloud-based DLP has made it far easier to adopt.
How is DLP different from encryption?
Encryption protects data from being read if it is stolen. DLP controls whether sensitive data can leave in the first place. They work best together.