Fix Civil 3D Startup Crashes by Verifying Required VC++ and .NET Runtimes
Issue:
Civil 3D may crash at launch, freeze during corridor rebuilds, display “Unhandled e0434352h – CLR Exception,” or silently fail to start. These problems often appear after Windows Updates, new installations, or version upgrades (2023–2026).
In many cases, the root cause is missing, outdated, or mismatched Microsoft Visual C++ (VC++) Redistributables or .NET Desktop Runtime components that Civil 3D relies on.
If even one required runtime is missing—or if a preview version is installed—Civil 3D’s .NET and native modules fail to load correctly.
Solution:
Verify and repair all required Microsoft VC++ and .NET runtimes to ensure they match the versions Civil 3D expects. Installing the correct runtimes (x64 + x86) resolves most silent startup failures, CLR exceptions, ribbon loading issues, and random instability.
Required Runtimes for Civil 3D (All Modern Versions)
Civil 3D 2022–2026 requires:
1. Microsoft Visual C++ 2015–2022 Redistributable
Install both:
x64 VC++ 2015–2022
x86 VC++ 2015–2022
Download:
https://aka.ms/vs/17/release/vc_redist.x64.exe
https://aka.ms/vs/17/release/vc_redist.x86.exe
2. .NET Runtime Requirements
Civil 3D Version Required Runtime
2020–2022 .NET Framework 4.8
2023–2024 .NET 6 Desktop Runtime (x64) + .NET Framework 4.8
2025–2026 .NET 8 Desktop Runtime (x64) + ASP.NET Core 8 Runtime
Download:
.NET 6 Desktop Runtime: https://dotnet.microsoft.com/en-us/download/dotnet/6.0
.NET 8 Desktop Runtime: https://dotnet.microsoft.com/en-us/download/dotnet/8.0
How to Fix and Verify Runtimes
1. Confirm installed runtimes
Go to ‘Add or Remove Programs’ or ‘Programs and Features’
You should see:
Microsoft.NETCore.App 6.x or 8.x
Microsoft.WindowsDesktop.App 6.x or 8.x
Microsoft.AspNetCore.App 6.x or 8.x
2. Repair VC++ Redistributables
Windows Start > Apps & Features
Search for Microsoft Visual C++ 2015–2022
For both x64 and x86:
Click Modify > Choose Repair
3. Repair .NET Desktop Runtime
Download the correct version for your Civil 3D installation, run the installer, choose Repair, and reboot.
