Terms of Service

Last updated: 20 October 2026

1. About these terms

1.1 These terms apply when you use:

• Kestrel, our Windows app for protection and backup (earlier versions were called Prius), and its background services;
• Aerie, our web console for organisations;
• Kestrel for Outlook;
• our cloud backup service;
• the customer portal on our website.

Together these are "the Service".

1.2 The Service is supplied by Prius Data Technologies Ltd ("PDTL", "we", "us"), a company registered in England and Wales under number 16589578. Our registered office is 71-75 Shelton Street, Covent Garden, London WC2H 9JQ, United Kingdom. You can reach us at support@priusdatatechnologies.co.uk or +44 1452 905055.

1.3 By creating an account, installing Kestrel or using the Service, you agree to these terms. If you accept them for an organisation, you confirm that you are authorised to bind it, and "you" means that organisation.

1.4 3SETS, PDTL's fitness app for iPhone, has its own terms at https://3sets.co.uk/terms-and-conditions, which apply to 3SETS instead of these terms.

1.5 Our Privacy Policy and our Data Retention & Account Deletion page explain how we handle data. They form part of these terms.

2. Your account

2.1 To use the Service you must:

• be at least 18;
• register with your name, a valid email address and a password, and optionally a company name;
• confirm your email address;
• set up an authenticator app. Two-factor sign-in is required on every account and cannot be switched off.

2.2 Keep your password and authenticator secure, and tell us straight away if you think someone else has used your account. PDTL will never ask for your password or authenticator code.

2.3 Each account has a licence. Please quote its licence number when you contact us.

2.4 You are responsible for what happens under your account, including what your organisation's administrators do in Aerie.

3. Free trial

3.1 New accounts start on a free trial. Its length and what it includes are shown on our Plans page. During the trial you can back up and restore within the trial's device and storage limits.

3.2 When the trial ends, backup and restore stop. You can then subscribe to a paid plan or delete your account.

3.3 If you do neither, your account and all backed-up files are permanently deleted after a grace period (currently 7 days after the trial ends). Deletion is carried out by a daily job, so it normally happens within a day of that date. Kestrel and the portal show the date.

4. Plans, prices and payment

4.1 Our plans, their prices, device limits and storage allowances are shown on our Plans page. The plan you are on when you subscribe applies until it changes under these terms.

4.2 Card payments are not open yet. To subscribe or change plan, choose a plan in Kestrel and select "Confirm and request". Nothing is charged when you make a request. Our team will contact you to confirm the price and how you will pay before any charge is made.

4.3 A plan change is refused if your account already has more authorised devices, or more stored data, than the new plan allows.

4.4 If a payment is overdue, we may stop new backups. Restores stay available while a payment issue is sorted out.

4.5 Plans renew monthly until cancelled. You can cancel at any time by emailing support@priusdatatechnologies.co.uk; the cancellation takes effect at the end of the period you have paid for.

4.6 We will give you at least 30 days' notice by email of any price increase. If you do not accept it, you may cancel before it takes effect.

4.7 Consumers' right to cancel. If you are a consumer, you may cancel a paid subscription within 14 days of starting it. If you asked us to start the service within those 14 days, we may deduct a proportionate amount for the service already provided. This does not affect your other statutory rights.

4.8 Features shown in Kestrel as "coming soon" are not part of any plan until they are released. We do not promise that they will be released, or when.

5. Devices

5.1 Each installation of Kestrel has its own device identity, and is authorised against your licence when you sign in, if your plan has room.

5.2 To remove a device and free its place, ask us or, for organisations, use Aerie. A removed device cannot back up or restore.

5.3 Only supported versions of Kestrel can connect. If your version is too old, Kestrel asks you to update. Kestrel checks every update's fingerprint before installing it.

6. Backup

6.1 Kestrel backs up the files in the folders you choose, by hand or on a schedule, while the computer is on and Kestrel is running. It sends only new or changed files. It does not back up Windows, installed programs or system settings unless you use a system image feature where your plan includes it.

6.2 Uploads that would take you over your plan's storage allowance are refused. Single files larger than 5 GB cannot currently be backed up.

6.3 You can restore the latest backed-up copy of each file while your plan allows restores.

6.4 Deleting a file on your computer does not delete its backup. Backups are removed when your account is deleted.

6.5 "Remove local copies after backup" is an option you can turn on for a backup set. It moves files to the Windows Recycle Bin once their upload is confirmed. Once you empty the Recycle Bin, the backup may be the only copy. You use this option at your own risk.

6.6 Backup reduces risk; it does not remove it. Check that the right folders are selected and that backups complete, and keep more than one copy of anything you cannot afford to lose.

7. Security features and Aerie

7.1 Kestrel's security features work alongside Microsoft Defender or your own antivirus. They do not replace antivirus software. No security product detects every threat; Kestrel can miss real attacks and can raise false alarms.

7.2 Organisations using Aerie. Aerie lets your administrators see security information from your computers and act on them remotely, including isolating a computer, ending processes, taking screenshots, finding a device's location, restarting, restoring a system image and uninstalling Kestrel. Some actions run without a notice on screen, and some cannot be undone. You agree that:

• you will only enrol computers you own or are authorised to manage;
• you will tell the people who use them about the monitoring and actions you use, and have a lawful basis for them;
• you are responsible for who you make an administrator, and for the actions they take;
• for personal data about your users, you are the controller and PDTL is your processor, and the processing terms in section 12 apply.

7.3 Kestrel's optional speed test uses your internet connection. Scheduled tests are skipped on connections Windows marks as metered, and you can change their interval or switch them off.

8. Acceptable use

You must not use the Service to:

• store or share material you have no right to hold, or that is unlawful;
• monitor or control any computer or person without the authority to do so;
• try to reach another customer's data, or get around plan limits or security controls;
• probe, attack, overload or reverse engineer the Service, except where the law allows;
• resell the Service without our written agreement.

9. Your content

9.1 Your files and data remain yours. You give PDTL permission to store, copy, process and transmit them only as needed to provide the Service.

9.2 You confirm that you have the right to back up the files you choose, including any that contain other people's personal data.

10. The software

10.1 We grant you a non-exclusive, non-transferable licence to install and use Kestrel and Kestrel for Outlook while your account is in good standing and within your plan's limits. All rights in the Service remain with PDTL and its licensors. Third-party open-source components are licensed under their own terms.

10.2 Kestrel includes background services that start with Windows so that scheduled backups and protection keep running.

11. Availability and changes

11.1 We aim to keep the Service available, but we do not guarantee that it will be uninterrupted or error-free. We may need to suspend it for maintenance or security reasons.

11.2 We may update the Service. An update may be required before backup or restore can continue.

11.3 We may change these terms. We will give you at least 30 days' notice by email or in Kestrel of any change that materially affects you, unless the change is required by law sooner. If you do not accept a change, you may cancel before it takes effect.

12. Processing terms for organisations

Where PDTL processes personal data for an organisation, PDTL will:

• process it only on the organisation's documented instructions, which are these terms and the organisation's use of Aerie;
• ensure that people authorised to process it are bound by confidentiality;
• take appropriate technical and organisational security measures;
• use the sub-processors listed in our Privacy Policy, and tell the organisation of any intended change so it can object;
• help the organisation respond to requests from individuals and meet its security and breach notification duties;
• notify the organisation without undue delay after becoming aware of a personal data breach affecting its data;
• delete the data when the account is deleted, as described on our Data Retention & Account Deletion page;
• make available the information reasonably needed to show compliance with these duties.

13. Suspension and termination

13.1 You can delete your account as described on our Data Retention & Account Deletion page.

13.2 We may suspend or close an account if payment is seriously overdue, if you materially breach these terms (in particular section 8), or if we must do so by law. Except where there is a security risk or a legal reason not to, we will tell you first and give you a reasonable chance to put things right and to restore your files.

14. Liability

14.1 Nothing in these terms limits liability for death or personal injury caused by negligence, for fraud, or for anything else that cannot be limited by law.

14.2 If you are a consumer, we are responsible for loss or damage you suffer that is a foreseeable result of our breaking these terms or failing to use reasonable care and skill. We are not responsible for loss that was not foreseeable. You keep all your statutory rights.

14.3 If you are a business:

• we are not liable for loss of profits, revenue, business or goodwill, or for any indirect or consequential loss;
• our total liability in any 12-month period is limited to the fees you paid for the Service in that period, or £100 if greater.

14.4 We are not responsible for loss of data where you could have avoided it by keeping your own copies, or for the results of actions your administrators take in Aerie.

15. Complaints, law and disputes

15.1 If you have a complaint, email support@priusdatatechnologies.co.uk. We aim to acknowledge it within 2 working days and resolve it within 14 days.

15.2 These terms are governed by the law of England and Wales, and the courts of England and Wales have jurisdiction. If you are a consumer living in Scotland or Northern Ireland, you may also bring proceedings there.

16. General

• You may not transfer your rights under these terms without our written agreement. We may transfer ours to another organisation, and will tell you if we do.
• If a court finds part of these terms unenforceable, the rest stays in force.
• These terms are the whole agreement between us about the Service.
• No one other than you and PDTL has any right to enforce these terms.
• Notices to us go to support@priusdatatechnologies.co.uk; notices to you go to your account email.

17. Contact

Prius Data Technologies Ltd, 71-75 Shelton Street, Covent Garden, London WC2H 9JQ, United Kingdom support@priusdatatechnologies.co.uk · +44 1452 905055