Cemu not launching or black screen on game start — complete fix guide

install-visual-cpp-runtime-and-rerun (sortOrder=1, isMostHelpful)

Cemu requires the 64-bit Microsoft Visual C++ Redistributable (2017 or later). If it's missing you get an 0xc000007b error, a "VCRUNTIME140.dll not found" message, or Cemu simply refuses to open. Install it from Microsoft and retry.

1. Download the latest Visual C++ Redistributable. Go to learn.microsoft.com and search for "Latest Microsoft Visual C++ Redistributable downloads." Download the X64 installer (even on a 64-bit system you need the x64 package — the x86 version is not sufficient for Cemu).
2. Run the installer. It takes under a minute. If the installer says "already installed — repair/uninstall," choose Repair to fix any corruption in the existing installation.
3. Reboot, then launch Cemu. Many runtime installations require a restart to take effect. After rebooting, try launching Cemu again before opening any game.
4. If Cemu opens but still won't start a game, also install the Visual C++ 2015 package (same page — both the 2015 and 2019/2022 packages may be needed). Some Cemu builds reference both runtimes.

switch-graphics-api-between-vulkan-and-opengl (sortOrder=2)

A black screen on game launch — especially with no error — almost always means Cemu is using the wrong graphics API for your GPU and driver. Switching between Vulkan and OpenGL (or vice versa) in Cemu's settings fixes this in the majority of cases.

1. Open Cemu, go to Options → General Settings → Graphics (the exact path may say Debug or Settings depending on your Cemu version).
2. Change the Graphics API. If it is currently set to Vulkan, switch to OpenGL. If it is already on OpenGL, switch to Vulkan. Click OK and close settings.
3. Update your GPU driver before testing Vulkan. Vulkan support on Cemu requires an up-to-date driver. For NVIDIA: GeForce Experience or nvidia.com; for AMD: AMD Software or amd.com; for Intel integrated graphics: intel.com. Outdated Vulkan drivers silently produce black screens. Once updated, retest with Vulkan — it typically performs better than OpenGL on modern hardware.
4. If Cemu crashes before you can open Settings (crash on launch before the UI appears), open the file settings.xml inside Cemu's user data folder and change the <GFXApi> value manually to OpenGL, save, and launch again. This bypasses the crash loop caused by a Vulkan initialisation failure.
5. AMD GPUs and Vulkan: Some AMD integrated and older discrete GPUs have known Cemu–Vulkan stability issues. If you have an AMD GPU and Vulkan black-screens or crashes, OpenGL is the more reliable choice until you verify your driver version against Cemu's release notes.

fix-shader-cache-stutter-and-first-play-performance (sortOrder=3)

Cemu compiles shaders the first time each one is encountered in a game. On first play this causes severe stutter (hitching every few seconds) that looks like hardware under-performance but is actually normal behaviour — it goes away once the shader cache is populated.

1. Understand this is temporary. The shader compilation stutter happens once per game on first play and then diminishes significantly on subsequent sessions as the cache warms. Playing through an area even with bad stutter builds the cache for future sessions. This is not a sign your PC can't run the game.
2. Enable async shader compilation. In Options → General Settings → Graphics, look for Async Shader Compile or similar. Enabling this compiles shaders in the background on separate threads instead of blocking the main thread, which dramatically reduces stutter at the cost of occasional pop-in on first encounters. This is recommended for all but the oldest CPUs.
3. Download a community shader cache if available. The Cemu community maintains pre-built shader caches for popular Wii U titles. Search for "[game name] Cemu shader cache" on community wikis or forums. A pre-built cache skips the first-play compilation entirely. Always scan downloaded files and only use caches from the established Cemu community — verify the source before extracting.
4. Place the shader cache correctly. Cemu looks for shader caches in its shaderCache/transferable subfolder (the file is named after the game's title ID). If you downloaded a cache, extract and place the .bin file there, then launch the game — stutter should be minimal from the first session.