Common installation errors
Find the message you're seeing, then work through the fix from top to bottom. The steps start with the quickest.
Error, cause and fix
| Error or symptom | Likely cause | Fix |
|---|---|---|
| "Windows protected your PC" (SmartScreen) | The installer is new or rarely downloaded, so it has little reputation yet. | Check that you downloaded it from the official site and that the file name matches. Click More info > Run anyway. Never do this for files from download portals. |
| "This app has been blocked for your protection" | An admin policy, or Smart App Control on Windows 11. | On a work PC, ask IT. At home, check Windows Security > App & browser control. Use the Microsoft Store or winget version if one exists. |
| "Access is denied" / "Error writing to file" | No admin rights, or antivirus is locking the file. | Right-click the installer > Run as administrator. Close the font manager if it's running. Pause third-party antivirus for the duration of the install only. |
| "This app can't run on your PC" | A 64-bit installer on 32-bit Windows, or an unsupported Windows version. | Check System type in Settings > System > About. Get the correct build or a supported release. See the compatibility page. |
Missing VCRUNTIME140.dll / MSVCP140.dll | The Microsoft Visual C++ Redistributable is missing. | Install the latest supported Visual C++ Redistributable (x64 and x86) from Microsoft's official site, then restart. |
| ".NET Framework required" | A required .NET component is disabled. | Control Panel > Programs > Turn Windows features on or off. Enable the .NET version requested, then run setup again. |
| Error 1603 / "A fatal error occurred during installation" (MSI) | A leftover older version, a pending restart, or a locked folder. | Restart Windows. Uninstall the old version from Settings > Apps, delete the leftover program folder, and run setup as administrator. |
| "Another installation is in progress" (Error 1618) | Windows Update or another installer is running. | Wait for updates to finish, or restart, then try again. |
| Installer does nothing when double-clicked | The download is incomplete or blocked (Mark of the Web). | Download it again. Right-click > Properties > tick Unblock if shown. Check Windows Security > Protection history. |
| "The file is not a valid font file" when adding fonts | A corrupt download, an unsupported format (for example a Mac-only suitcase or bitmap font), or a font inside an unextracted ZIP. | Extract ZIPs first. Download the font again. Use OTF, TTF or TTC on Windows. Use the manager's check for corrupt fonts. |
| License or sign-in errors (commercial tools) | A trial has expired, or an account or network problem. | Check the system clock and internet connection, and whether a proxy or firewall is blocking the app. Sign out and back in. Contact the developer's support. |
Clean reinstall checklist
Export your collections
If the app still opens, export collections and sets, and note your settings.
Uninstall
Go to Settings > Apps > Installed apps, choose the font manager, and click Uninstall.
Restart Windows
This releases any font files and services that are still locked.
Remove leftovers (optional)
Rename the app's folder in
%APPDATA%or%LOCALAPPDATA%, for example by adding.old, rather than deleting it, so you can restore your settings if needed.Reinstall from the official source
Get a fresh copy using the address on our Download page and run it as administrator.