Block programs from loading untrusted fonts in Windows 10

Microsoft implemented a new security feature in Windows 10's November update build that added an option to the operating system to block the loading of untrusted fonts.
The use of fonts has always been problematic in the Windows operating system from a security point of view as bugs in font-handling code could give attackers high-level privileges.
Bulletins such as MS15-078 indicate that the Windows font system is targeted regularly, and one way to mitigate the impact of these attacks was the new untrusted font blocking security feature built-into Windows 10.
I have mentioned the feature when I reviewed the new version of Microsoft EMET, as it shipped with support for it, but it has been likely missed by at least some users, hence this new article.
Untrusted fonts blocking
The security feature needs to be enabled in the Windows Registry, and there for every machine that you want to enable the feature on.
- Tap on the Windows-key, type regedit.exe and hit enter.
- Confirm the UAC prompt if it is displayed.
- Navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Kernel\
- Right-click on Kernel, and select New > QWORD (64-bit) Value and name it MitigationOptions.
- Double-click on MitigationOptions afterwards and use one of the following values for the feature:
- To turn it on: 1000000000000
- To turn it off: 2000000000000
- To set it to audit mode: 3000000000000
Note: It is highly suggested to set the untrusted font blocking security feature to audit mode first, as you may run into issues with third-party applications after enabling the feature on a machine running Windows 10.
Alternatively, if you are running Microsoft EMET 5.5 on the machine, you may enable the "block untrusted fonts" feature using the application interface.
If you set it to audit mode, all blocked font loading attempts are written to the event log.
- Tap on the Windows-key, type eventvwr.exe and hit enter.
- Navigate to Application and Service Logs/Microsoft/Windows/Win32k/Operational.
- Scroll down to EventID: 260 and review the entries you find there.
Configuring exceptions
Some programs may not load or display correctly after you enable untrusted font blocking in Windows 10. While you may be able to resolve some of the issues directly, for instance by enforcing the use of system fonts in the application, you may run into issues with some apps where that is not an option.
Microsoft added an option to the security feature that enables you to set exceptions for these processes.
- Tap on the Windows-key, type regedit.exe and hit enter.
- Confirm the UAC prompt.
- Navigate to HKEY_LOCAL_MACHINE\ Software\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\
- Right-click on Image File Execution Options, and select New > Key.
- Use the full file name of the process that you want to exclude, e.g. winword.exe or firefox.exe, so that the key looks like this HKEY_LOCAL_MACHINE\ Software\Microsoft\Windows NT\CurrentVersion\Image File Execution Options\firefox.exe.
- Repeat this for every process you want to exclude.
Additional information about the blocking of untrusted fonts are available on Microsoft's Technet website.
Side Note: Google enabled the feature individually for its Chrome web browser running on Windows 10 recently according to an Ars Technica report improving security for Chrome users on Windows 10 in the process.


What mental age of reader are you targeting with the first sentence? 10?
Why not write an article on how to *avoid* upgrading from W10 to W11. Analogous to those like me who avoided upgrading from 7 to 10 for as long as possible.
If your paymaster Microsoft permits it, of course.
5. Rufus
6. Ventoy
PS. I hate reading these “SEO optimized” articles.
I used Rufus to create an installer for a 6th gen intel i5 that had MBR. It upgraded using Setup. No issues except for Win 11 always prompting me to replace my local account. Still using Win 10 Pro on all my other PCs to avoid the bullying.
bit pointless to upgrade for the sake of upgrading as you never know when you’ll get locked out because ms might suddenly not provide updates to unsupported systems.
ps…. time travelling?
written. Jan 15, 2023
Updated • Jan 13, 2023
This happens when you schedule a post in WordPress and update it before setting the publication date.
Anyone willing to downgrade to this awful OS must like inflicting themselves with harm.
I have become convinced now that anybody who has no qualms with using Windows 11/10 must fit into one of the following brackets:
1) Too young to remember a time before W10 and W11 (doesn’t know better)
2) Wants to play the latest games on their PC above anything else (or deeply needs some software which already dropped W7 support)
3) Doesn’t know too much about how computers work, worried that they’d be absolutely lost and in trouble without the “”latest security””
4) Microsoft apologist that tries to justify that the latest “features” and “changes” are actually a good thing, that improve Windows
5) Uses their computer to do a bare minimum of like 3 different things, browse web, check emails, etc, so really doesn’t fuss
Obviously that doesn’t cover everyone, there’s also the category that:
6) Actually liked W7 more than 10, and held out as long as possible before switching, begrudgingly uses 10 now
Have I missed any group off this list?
You have missed in this group just about any professional user that uses business software like CAD programs or ERP Programs which are 99% of all professional users from this list.
Linux doesn’t help anyone who is not a linux kid and apple is just a fancy facebook machine.
Microsoft has removed KB5029351 update
only from windows update though
KB5029351 is still available from the ms update catalog site
1. This update is labaled as PREVIEW if it causes issues to unintelligent people, then they shouldn’t have allowed Preview updates ot install.
2. I have installed it in a 11 years old computer, and no problems at all.
3. Making a big drama over a bluescreen for an updated labeled as preview is ridiculous.
This is probably another BS internet drama where people ran programs and scripts that modified the registry until they broke Windows, just for removing stuff that they weren’t even using just for the sake of it.
Maybe people should stop playing geeks and actually either use Windows 10 or Windows 11, but don’t try to modify things just for the sake of it.
Sometimes removing or stopping things (like defender is a perfect example) only need intelligence, not scripts or 3rd party programs that might mess with windows.
Windows 11 was a pointless release, it was just created because some of the Windows team wanted to boost sales with some sort of new and improved Windows 10. Instead, Microsoft cannot support one version well let alone two.
Windows 11 is the worst ugly shame by Microsoft ever. They should release with every new W11 version a complete free version of Starallback inside just to make this sh** OS functionally again.
motherboard maker MSI has recently released a statement regarding the “unsupported processor” blue screen error for their boards using Intel 600/700 series chipsets & to avoid the KB5029351 Win11 update:
https://www.msi.com/news/detail/MSI-On–UNSUPPORTED-PROCESSOR–Error-Message-of-Windows-11-Update-KB5029351-Preview-142215
check out the following recent articles:
Neowin – Microsoft puts little blame on its Windows update after UNSUPPORTED PROCESSOR BSOD bug:
https://www.neowin.net/news/microsoft-puts-little-blame-on-its-windows-update-after-unsupported-processor-bsod-bug/
BleepingComputer – Microsoft blames ‘unsupported processor’ blue screens on OEM vendors:
https://www.bleepingcomputer.com/news/microsoft/microsoft-blames-unsupported-processor-blue-screens-on-oem-vendors/
While there may be changes or updates to the Windows 10 Store for Business and Education in the future, it is premature to conclude that it will be discontinued based solely on rumors.
My advice, I left win 15 years ago. Now I’m a happy linux user (linuxmint) but there is Centos, Fedora, Ubuntu depending on your needs.
motherboard maker MSI has recently released new BIOS/firmware updates for their Intel 600 & 700 series motherboards to fix the “UNSUPPORTED_PROCESSOR” problem (Sept. 6):
https://www.msi.com/news/detail/Updated-BIOS-fixes-Error-Message–UNSUPPORTED-PROCESSOR–caused-BSOD-on-MSI-s-Intel-700-and-600-Series-Motherboards-142277