A window takes over the screen, a siren sounds, a recorded voice announces that the computer is infected and that you must immediately call a number to avoid losing your files. This is the typical scenario of the fake tech support scam. Service-Public.fr describes it as follows: a message makes you believe there is a serious technical problem and a risk of data loss, to push the victim to call a fake support service that will charge them for a so-called repair or make them buy useless, or even harmful, software.
The phenomenon is far from marginal. According to the 2024 activity report of Cybermalveillance.gouv.fr, cited by Microsoft France in July 2025, it is the third-largest cyber threat for individuals, with 13,500 requests for assistance over the year. The Paris public prosecutor’s office received 585 complaints for offences committed in 2023, for losses estimated at €374,000. Losses per victim, long a few hundred euros, can now reach several thousand, or even tens of thousands of euros.
How to recognise fake tech support
A few signs are enough to tell. According to Microsoft‘s help page, genuine Windows error messages never contain a phone number to call, and the company does not call you to report a problem with your device if you have not contacted it first. The other warning signs mentioned: a window that seems to lock the whole computer, audible alarms, an urgent tone threatening serious consequences, a request for remote access, then a request for payment.
In its July 2025 press release, Microsoft adds that it never asks for payment in cryptocurrency or gift cards. The investigation by Que Choisir, published in October 2021, explained where these alerts come from: they are often distributed through hijacked advertising networks, which are triggered on streaming, gaming or recipe sites. The “technician” who answers then takes control of the computer, simulates a diagnosis and charges for the intervention, generally between €150 and €500, sometimes up to €1,000, according to the amounts recorded by the magazine in 2021.
Locked screen: what to do right away
As long as you have neither called nor paid, nothing is lost. The message itself generally does nothing more than lock the browser.
- Do not call the number displayed and do not click any button in the window. If someone called you out of the blue, hang up.
- Close the browser. Microsoft recommends the ALT+F4 shortcut if the mouse no longer responds. Que Choisir also suggested, in 2021, opening the task manager, ending the browser task, then restarting it without restoring the previous session.
- Restart the computer if the window persists. As a last resort, the magazine states that holding down the power button does not cause any loss of your data.
- Take stock online: Service-Public.fr refers to the free diagnosis tool of Cybermalveillance.gouv.fr, the French public victim assistance service, which details the recommendations to follow in this situation.
- Warn those around you, as Microsoft suggests, especially elderly relatives. An Ifop study for Microsoft from May 2025 shows that only 16% of 60-to-75-year-olds know precisely what steps to take in the event of an online scam.
You called, gave access or paid: what to do
If the scammer has taken control of your computer or obtained your bank details, the situation requires more rigour. The goal is to cut off their access, block the money and keep evidence.
- Have the computer checked by a trusted repairer, as Que Choisir recommends when the victim has let a stranger take control.
- Change your passwords, especially those for your bank and email, as Que Choisir advised: a scammer who had control of the computer may have picked up login credentials.
- Call your bank. If your card details were shared, block the card with your bank or through the interbank service on 0 892 705 705, open 7 days a week, 24 hours a day (premium-rate number), says Service-Public.fr. Note the registration number you are given: it is the dated record of your request.
- Dispute transactions you did not make. According to Service-Public.fr, a fraudulent payment more than 13 months old can no longer be refunded; in other cases, the bank must refund immediately and, at the latest, by the end of the business day following the dispute. Reporting on the Perceval platform, accessible with FranceConnect, provides a receipt that you must send to your bank.
- File a complaint at the police station or gendarmerie, with screenshots, the number called and statements. The Paris public prosecutor’s office also invites victims to send it a complaint letter directly, which speeds up processing, according to the July 2025 press release.
- Report the impersonation to the company being imitated: Microsoft has a dedicated page, microsoft.com/reportascam.
An important nuance: a payment that you yourself approved for the “repair” does not fall within the definition of fraud used by Service-Public.fr, which assumes that you did not make the purchase. Que Choisir warned in 2021 that the bank may refuse to cancel it if it considers there was negligence. Hence the importance of acting quickly and documenting every exchange.
Protecting yourself in the future
In the same press release, Microsoft advises downloading software only from the Microsoft Store or publishers’ official websites, and treating any window displaying a phone number as suspicious. For a small business, the useful reflex is to explain this scenario to every employee: a locked computer at the office should be reported to the person in charge of IT, never dealt with by calling a number found on the screen.
Frequently asked questions
Is my computer really infected?
Most often, no: the window is a web page designed to frighten. If you let a stranger install software, a check by a professional is essential.
Can Microsoft or Apple call me about a virus?
Microsoft states that it never contacts its customers directly by phone or by on-screen message to offer technical support.
Can I get back the money paid to the fake technician?
It is difficult: in 2021, Que Choisir noted that scammers operate from abroad and cover their tracks, which leaves little chance of recovering the money. Notify your bank without delay and file a complaint.
Should I file a complaint even if I paid nothing?
It is not essential, but keep screenshots: Microsoft encourages reporting any attempt at microsoft.com/reportascam. For a specific case, the Cybermalveillance.gouv.fr diagnosis tool points you to the right course of action.
Sources
- Recommandations à suivre en cas d'arnaque au faux support technique — Service-Public.fr, 2025-04-08
- Fraude à la carte bancaire — Service-Public.fr, 2026-02-13
- Microsoft, Cybermalveillance.gouv.fr et le Parquet de Paris appellent à se mobiliser contre les arnaques au faux support technique — Microsoft France, 2025-07-10
- Protégez-vous contre les escroqueries et les attaques en ligne — Microsoft Support, 2026-11-12
- Arnaque au faux support technique – Ne payez pas ! — Que Choisir, 2021-10-21