How to block incognito mode, and how well it actually holds

Two different jobs, and only one of them is yours

There is no button inside Chrome, Edge, Firefox or Safari that removes private browsing. Every route that works sits one level up — in the account, in the device’s parental controls, or in an administrative policy — and which one applies depends on a question about you rather than about the browser.

If you administer the device, because it is a work laptop, a school machine or your own computer, the route is a policy setting. Chrome’s is called IncognitoModeAvailability, it has three values, and the one that matters here is the middle one. Google’s description: “If ‘Disabled’ is selected, pages may not be opened in Incognito mode.” On Windows the value lives in the registry under Software\Policies\Google\Chrome\IncognitoModeAvailability. One caveat comes with it, in Google’s own words: another policy “takes precedence over this policy and can re-enable Incognito mode for specific URLs”, so a machine that already has an allowlist is not as closed as the first setting suggests.

If somebody else uses the device day to day — a child, most often — the registry is the wrong tool and the wrong altitude. The platforms have parental controls that do this as one of the things they do, and the difference between them is not the setting: it is how far the block reaches.

The routes the platforms document for a parent

Google, through Family Link. When a child’s Google Account is supervised, the block is not something you switch on: it comes with the account. Google states it on its own help page, and repeats it under each type of device: “Incognito mode is turned off when your child is signed in to Chrome with an account managed by Family Link.” On a Chromebook, where the account is the whole machine rather than one app, Google puts it more bluntly still: “Children can’t browse in private.”

Microsoft, through Family Safety. Edge answers the same question under a heading of its own — when InPrivate browsing is unavailable — and the answer names both cases: “Children with activity reporting or web filtering enabled through their family group can’t browse InPrivate. Organizations, like schools or workplaces, can use group policy to prevent people from browsing InPrivate.” Microsoft also closes the obvious side door, which is the part worth knowing: with the web filter on, “unsupported browsers are blocked so that filtering cannot be bypassed”.

Apple, through Screen Time. Apple documents the restrictions themselves clearly enough: Settings, then Family, then your child’s name, then Apps & Websites, then Restrictions, then Filtering under Websites, where the choice is “Limit Adult Websites or Ask to Browse. To use Ask to Browse, just set to Approved Websites Only”. What Apple does not do, on either of the two pages we read again on 16 September 2026, is say what those restrictions do to Safari’s Private Browsing. The phrase does not appear on the parental controls page, and Screen Time is never mentioned on Apple’s own page about turning Private Browsing on and off. That is a silence rather than a denial, and it is reported here as a silence.

How well it holds, which is a question about the device

This is the part that decides whether any of it was worth doing, and Google is the only party in this whole discussion that publishes both halves. On the same page as the block, one paragraph above it, is a warning printed twice.

For a computer: “On Windows, Mac, or Linux computers: Your child can sign out of Chrome and switch to other profiles, which takes them to a browsing experience where Family Link settings for Chrome won’t apply. They may also have access to other browsers where Family Link settings for Chrome won’t apply.” For an iPhone or iPad, the same warning with one clause gone, because there are no other profiles to switch to: “Your child can sign out of Chrome, which takes them to a browsing experience where Family Link settings for Chrome won’t apply. They may also have access to other browsers where Family Link settings for Chrome won’t apply.”

So the block is not one thing with one strength. On a Chromebook it holds, because the account is the machine and there is nowhere else to go. On Android it covers Chrome, and whether another browser can be installed is a separate control in the same app. On a Windows or Mac computer and on an iPhone, Google says in writing that it can be stepped around by signing out or opening something else. Microsoft’s answer to the same problem is to block the other browsers as part of the filter, which is why its wording is worth reading next to Google’s rather than instead of it.

None of that makes the setting pointless. It makes it a speed bump on some devices and a wall on others, and knowing which one you have is the difference between a control and the feeling of one.