Smart App Control is blocking a game, launcher or mod
Smart App Control blocks unknown unsigned code by default, which is exactly what a lot of mods, mod loaders, older launchers and hardware utilities are. Before you turn it off, find out what it actually blocked — Windows records it under Protection history. Turning it back on is no longer the gamble it was: Microsoft's FAQ says recent Windows updates let you enable it from the Windows Security app, and as of 6 October 2026 its developer overview no longer carries the clean-install-only requirement it used to. Check your own toggle after switching it off, and remember that while it is off, unknown unsigned code runs without this check.
This feature is different from the rest of Windows Security in a way worth understanding before you touch it. It is not a scanner that flags things it recognises as bad — it is an allowlist that runs code only if Microsoft's service predicts it is safe or it carries a certificate from a trusted authority. Anything niche, anything unsigned, and anything a small team ships without code signing falls outside that by default, whether or not it is dangerous.
Symptoms
- A pop-up saying Smart App Control has blocked part of this app
- A game launches but a specific feature — an overlay, anti-cheat module, mod loader or hardware plugin — does nothing
- An installer closes immediately with no error
- A mod manager or trainer disappears the moment you run it
- A driver from a peripheral utility refuses to load
- It started right after a clean install or a reset, or after a toast notification about enforcement mode
Why this happens
The file is unsigned, and unsigned is the default block
Smart App Control allows apps and binaries only when they are likely to be safe. Malware, potentially unwanted apps and unknown unsigned code are blocked by default. Where the prediction service has no opinion, a certificate from a certificate authority in the Trusted Root Program is what gets a file through. Community mods, small utilities and older tools frequently have neither — the prediction service has never seen them, and nobody paid for a signing certificate.
Find out exactly what was blocked · Get a signed build, or the file from its real source
The app runs, but one of its components does not
The most confusing version of this is when nothing appears broken at first. Microsoft's own description of the message is that an app, service or piece of hardware tried to load a driver or file that is not properly signed, and that only that file stops working — the rest of the application carries on. That is why a game can launch normally with its overlay, capture or peripheral integration silently dead.
Enforcement mode turned itself on
Smart App Control starts in evaluation mode, watching what you install and run without blocking anything, and decides whether the machine is a good fit. Microsoft says it turns itself on in most cases, and turns itself off for users whose normal work it would interrupt — developers and corporate users are the examples given. You get a toast notification when it enters enforcement mode, which is easy to dismiss and forget about weeks before the first thing breaks.
Fixes
Find out exactly what was blocked
about 5 minEvery decision after this depends on whether the blocked file is something you trust. Guessing is how people end up disabling a security feature over a file they would not have run anyway.
Applies to: Windows 11 where Smart App Control is present
- If the pop-up is still on screen, select Learn more. It names the driver or file that was blocked.
- If it has gone, open Windows Security > Virus & threat protection > Protection history and search the entries for Smart App Control or Blocked app.
- Look at where the blocked file came from. A file inside a game you installed from Steam or the publisher's own installer is a different proposition from one that arrived with a mod pack from a file host.
- If you do not recognise it, stop. A block on something you cannot account for is the feature doing its job, and the answer is not to switch the feature off.
Confirmed by the vendor.
Source: Microsoft
Check which mode Smart App Control is in
about 3 minEvaluation mode does not block anything, so if you are in it, this is not your problem at all.
Applies to: Windows 11 where Smart App Control is present
- Open Windows Security > App & browser control and find the Smart App Control section. If there is no such section, the feature is not on this device and you can stop here.
- On means enforcement mode — it is actively blocking. Evaluation means it is observing without blocking. Off means it is not running.
- If it says Evaluation and something is still being blocked, the block came from somewhere else: Microsoft Defender, SmartScreen, memory integrity, or the game's own anti-cheat. Check Protection history to see which.
- Smart App Control starts in evaluation mode, so it may have switched itself to enforcement since you set this machine up.
Confirmed by the vendor.
Source: Microsoft
Get a signed build, or the file from its real source
about 20 minA properly signed file is allowed through even when Microsoft's prediction service has no opinion on it. This solves the problem without weakening anything.
Applies to: Windows 11 where Smart App Control is present
- Re-download the tool from the developer's own site or repository rather than a mirror or aggregator. Repackaged copies lose the original signature.
- Check for a newer release. Projects that get caught by this often ship a signed build afterwards precisely because of the complaints.
- For peripheral and RGB utilities, install the manufacturer's current package rather than an old one you already had — the old driver inside it is usually what triggers the block.
- If the project has no signed build, report it to them. There is nothing you can configure on your side that makes an unsigned binary acceptable to this feature.
Confirmed by the vendor.
Source: Microsoft
Turn Smart App Control off
Check before applyingabout 10 minMicrosoft itself suggests this for installers that use files which cannot be signed. It is also the step you may not be able to reverse, so treat it accordingly.
Applies to: Windows 11 where Smart App Control is present
Before you do this
While Smart App Control is off, unknown unsigned code runs without this check — that is the whole point of the feature, so turn it back on when you are done. Re-enabling should be available to you: Microsoft's FAQ says recent Windows updates allow it to be enabled from the Windows Security app without a clean installation, and its developer overview no longer carries the earlier clean-install-only statement as of 6 October 2026. Confirm the On option is still there on your own machine before you install anything else.
- Confirm first that you trust the specific file you identified earlier, and that you got it from its real source.
- Open Windows Security > App & browser control > Smart App Control and set it to Off.
- Do what you needed to do — complete the install, or run the tool.
- Go straight back to the same screen, confirm the option to turn it on again is available to you, and turn it back on once you are done.
- If the On option is missing on your machine, install any pending Windows updates and re-check. Microsoft no longer documents a clean-install-only requirement, so do not reinstall Windows on the strength of the older guidance.
Confirmed by the vendor.
Known issues
Microsoft's two pages used to disagree about whether Smart App Control can be re-enabled after being turned off. That is now resolved: as of 6 October 2026 the developer overview no longer says it can only be enabled on a clean install, and no longer gives a build 22572 floor or regional limits. The FAQ's position stands — recent Windows updates allow enabling it from the Windows Security app without a clean installation.
Affects Windows 11 where Smart App Control is present · Status: fixed
Some older Microsoft-signed binaries are blocked deliberately, because attackers can use them to gain unauthorized access. An app that bundles one of these will be blocked even though the file is genuinely from Microsoft.
Affects Windows 11 where Smart App Control is present · Status: open
If none of this worked
If Windows Security has no Smart App Control section at all, something else blocked your app — SmartScreen, Microsoft Defender, memory integrity refusing an unsigned driver, or the game's own anti-cheat rejecting an injected module. Protection history distinguishes them. Enterprise-managed machines and devices in S mode do not run Smart App Control, so on a work laptop the block is almost certainly a policy set by your IT department, and disabling anything locally will not help. If the blocked component is part of a mod that hooks into an online game, be careful about the fix you choose — getting it running may matter less than whether the game's anti-cheat will tolerate it.
Common questions
- Can I add an exclusion for one app?
- No. Smart App Control has no per-app allowlist you can edit — it is either enforcing for everything or off for everything. That design is the reason this page spends so much effort on identifying what was blocked: the only choices are to get a signed version of the file or to turn the whole feature off.
- If I turn it off, can I turn it back on?
- Yes. Microsoft's FAQ says recent Windows updates allow Smart App Control to be enabled from the Windows Security app without a clean installation, and as of 6 October 2026 its developer overview no longer states the clean-install-only requirement it previously carried. The practical approach is still to turn it off, do the one thing you needed, then go straight back to the same screen and turn it on again before you install anything else.
- Why did it start blocking things weeks after I installed Windows?
- Because it spends that time in evaluation mode, watching what you install and run without blocking anything, and then decides whether the machine is a good fit for enforcement. When it switches over you get a toast notification — which is easy to miss.
- Is Smart App Control the same as SmartScreen?
- No. SmartScreen warns you about files and sites with poor reputation and lets you continue anyway. Smart App Control is an allowlist: code runs only if Microsoft's app intelligence predicts it is safe or it carries a certificate from a trusted authority, and there is no button to proceed regardless. That is why an app blocked by Smart App Control fails silently rather than asking you a question.
- I only need to install one thing. Is turning it off temporarily reasonable?
- Sometimes, but do it deliberately: identify the blocked file first, get the installer from its real source, turn the feature off, install, and then check whether you can turn it back on. The risk is not the ten minutes it is off — it is finding out afterwards that On is no longer available on your build.
Did this fix work?
If a step is wrong, outdated, or did not help, telling us is the fastest way to get it corrected. Reports are reviewed before new articles.
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Sources
- Smart App Control overviewOfficial
Microsoft · Documentation · checked Oct 12, 2026
- Smart App Control only allows apps and binaries to run if they are likely to be safe, and blocks malware, potentially unwanted apps and unknown unsigned code by default
- If the app intelligence service cannot make a prediction, Smart App Control still allows an app signed with a certificate from a CA in the Trusted Root Program
- Evaluation mode observes activity without blocking; enforcement mode actively blocks
- The mode is shown at Settings > Windows Security > App and Browser Control as On, Evaluation or Off
- Microsoft automatically turns Smart App Control off for users whose regular work it would interrupt too often, such as developers and corporate users
- A toast notification appears when Smart App Control enters enforcement mode
- Some older Microsoft binaries are treated as unsafe because attackers can use them for unauthorized access
Microsoft · Support page · checked Oct 12, 2026
- Smart App Control checks whether Microsoft's cloud-powered security service can make a confident prediction about an app's safety
- Microsoft states that recent Windows updates allow Smart App Control to be enabled within the Windows Security app without requiring a clean installation
- Smart App Control can be disabled from the Windows Security app settings
- Microsoft lists enterprise-managed devices and devices running Windows in S mode among the reasons Smart App Control could be turned off
Microsoft · Support page · checked Oct 12, 2026
- The message means an app, service or piece of hardware tried to load a driver, app or other file that is not properly signed
- Microsoft says the rest of the app may continue to work fine when one file is blocked
- The Learn more button in the pop-up identifies which driver or file was blocked
- Blocked items are recorded under Windows Security > Virus & threat protection > Protection history, where Microsoft says to look for Smart App Control or Blocked app entries