Fonts Not Activating/Deactivating

General Questions

Why do some fonts get "stuck" and require a Windows restart?

Quick Answer: Windows has built-in security protections that occasionally lock font files to prevent malicious attacks. When this happens, a restart is needed to clear the lock. This is a Windows security feature, not a bug in FontPilot.

Understanding the Issue

What's Actually Happening?

When you install or uninstall fonts in Windows, the operating system's font security system (fontdrvhost.exe) takes control of those font files. Sometimes this system maintains a "lock" on font files even after FontPilot has completed its operation. When this happens, you'll see one of these symptoms:

Unable to install a font (even though it appears to install)
Unable to uninstall a font (gets an "access denied" or "file in use" error)
Font changes don't take effect until after restart
FontPilot operations can appear to succeed but Windows doesn't reflect the changes (if FontPilot sees this is happening, we will give you a heads up)

Why Does Windows Do This?

This behavior is actually protecting you from serious security threats. On Windows 8.1 and earlier versions, fonts were processed directly in the Windows kernel, making them a potential attack vector. Since Windows 10, fonts are processed in an isolated security container called fontdrvhost.exe.

Here's what changed and why:

Before Windows 10: Fonts had direct access to the Windows kernel (the core of your operating system). This meant a malicious font could completely take over your computer.

After Windows 10: Fonts are now processed in an isolated "sandbox" called an AppContainer. This protects your system, but occasionally causes the sandbox to maintain locks on font files.

The Security Context

Between 2015-2020, security researchers discovered multiple critical vulnerabilities in font handling:

CVE-2020-0938 & CVE-2020-1020: Allowed attackers to escape browser sandboxes
CVE-2020-1355: Remote code execution vulnerability in Windows Font Driver Host

These weren't theoretical risks—Google's Project Zero found these vulnerabilities being actively exploited in real-world attacks. Microsoft's response was to completely redesign font handling with security as the top priority.

Please see the following disclosures:

Why FontPilot's Approach is Actually Better

Registry-Based Installation (What FontPilot Uses)

FontPilot uses the Windows Registry method—the same approach Windows itself uses internally. Here's why this is the superior choice:

✅ Advantages:

Native Windows Integration: Works directly with Windows' font system
Maximum Compatibility: All applications recognize the fonts properly
Clean Uninstalls: Registry entries can be removed without residual files
Proper Font Metadata: Windows correctly identifies font names, weights, and styles
System-Level Recognition: Fonts appear in all font menus and applications

⚠️ Trade-off:

Subject to Windows security locks (requiring occasional restarts)

Alternative Methods and Why They're Problematic

Symlink Method (used by other common font management apps)

Creates symbolic links to font files
❌ Links break when original files move
❌ Doesn't work with all applications
❌ Windows Updates can break symlinks
❌ Fonts may not appear in system font lists

Adobe's Proprietary Method

Uses Adobe-specific font activation
❌ Only works reliably with Adobe applications
❌ Requires Adobe services running constantly
❌ Consumes more system resources
❌ Not a system-wide solution

Direct File Copying (Basic method)

Simply copies fonts to the Fonts folder
❌ No proper registration
❌ Applications may not detect the fonts
❌ Can leave orphaned files
❌ No metadata management

Practical Workarounds

When You Encounter a Locked Font

1 Wait and Retry

Sometimes waiting 10-15 seconds and retrying works
The lock may release on its own

Close Font-Using Applications
- Close any applications that might be using fonts (design apps, browsers, Office)
- Try the operation again
Clear Font Cache (Advanced)
- Open Services (services.msc)
- Stop "Windows Font Cache Service"
- Navigate to C:\Windows\ServiceProfiles\LocalService\AppData\Local\FontCache
- Delete cache files
- Restart the service
Use Safe Mode (Last Resort)
- Restart Windows in Safe Mode
- Fonts are less likely to be locked in Safe Mode
- Perform your font operations
- Restart normally

Best Practices to Minimize Issues

Install fonts in batches rather than one at a time
Close design applications before installing/uninstalling fonts
Avoid installing fonts from untrusted sources (this triggers more aggressive security checks)
Schedule font management during natural restart times (e.g., end of workday)

Frequently Asked Questions

Q: Is this a bug in FontPilot?

A: No, this is a Windows security feature. FontPilot correctly requests font operations through the proper Windows APIs. The lock occurs at the Windows system level, outside of FontPilot's control.

Q: Will this be fixed in a future version?

A: Because this is a Windows security feature, not a bug, it cannot be "fixed" without compromising system security. We continue to explore workarounds that maintain security while improving user experience.

Q: Why don't other font managers have this problem?

A: They do, or they use inferior methods:

Apps using the registry method (like FontPilot) experience the same Windows locks
Apps using symlinks avoid locks but sacrifice compatibility and reliability
Apps that never experience locks likely aren't properly integrating with Windows

Q: Is my system at risk when fonts are locked?

A: No, the opposite is true. The lock indicates Windows security is actively protecting your system. The inconvenience is a side effect of this protection.

Q: Can I disable this security feature?

A: We strongly recommend against attempting to disable Windows font security features. Doing so would expose your system to serious vulnerabilities that have been actively exploited in the wild.

The Bottom Line

The occasional need to restart is frustrating, but it's a small price for protection against serious security threats. Font-based attacks have been used to:

Steal sensitive data
Install malware
Take complete control of systems
Escape browser sandboxes

FontPilot uses the most reliable, compatible method for font management. While this means we're subject to Windows security locks, it ensures your fonts work properly across all applications when they are installed.

We're continuously monitoring Windows updates and exploring ways to minimize these occurrences while maintaining the security and compatibility benefits our users expect.

Need More Help?

If you're experiencing persistent issues beyond occasional locks:

Check our troubleshooting guide for specific error messages
Contact support with your Windows version and specific symptoms
Join our community forum to share experiences with other users

Remember: A restart requirement is annoying but normal. Consistent failures or errors may indicate a different issue we can help resolve.

Need more help? Contact support

FontPilot Documentation