Unreal Engine Shaders Compiling Forever (Stuck at 45%)

How to fix it

Try these in order — the most common fix is first.

1. 1. Verify it is really working

   Copy steps
   1. Open Task Manager and look for many ShaderCompileWorker processes using CPU
   2. Tail the newest log in Saved/Logs to see shaders being processed
   3. If CPU is busy, wait; restarting repeats the work
   Did this fix it? Yes No

2. 2. Fix the Derived Data Cache

   Copy steps
   1. Default location: C:\Users\<you>\AppData\Local\UnrealEngine\Common\DerivedDataCache
   2. Close the editor, back up, then clear it and relaunch
   3. Keep the cache on an SSD with free space
   Did this fix it? Yes No

3. 3. Unblock shader workers

   1. Add ShaderCompileWorker.exe and the editor to antivirus exclusions and the Windows firewall allow list
   Did this fix it? Yes No

4. 4. Last-resort config changes

   1. Some users report editing ConsoleVariables.ini or r.Shaders.AllowCompilingThroughWorkers; back up config files first and treat these as unofficial
   Did this fix it? Yes No

Symptoms

Editor loading sticks at 45% 'Compiling Shaders', or the shader counter in the corner never reaches zero; the first launch of a project can take hours.

Why it happens

• First launch of a new project or engine version has thousands of shaders to compile
• Slow CPU, HDD, or too few cores
• Corrupt or inaccessible Derived Data Cache
• Shader compile workers blocked by antivirus or firewall
• Engine bug in a specific version

This guide also covers

• unreal engine stuck compiling shaders
• unreal engine stuck at 45%
• unreal engine shaders compiling forever

The same problem in other apps

All export, render & quality loss guides →

• Unity Build Failed (Unity)
• Blender Crashing When Rendering (Blender)

Other Unreal Engine errors

• Unreal Engine Fatal Error Crash
• Unreal Engine GPU Crashed or D3D Device Removed
• Unreal Engine Out of Video Memory Error
• Unreal Engine Project Won't Open After Upgrade
• Epic Games Launcher Stuck Installing Unreal Engine
• Unreal Engine Packaging Failed (Unknown Cook Failure)
• Unreal Engine Visual Studio C++ Build Errors
• Unreal Engine 5 Lumen and Nanite Low FPS