: Ensure you download the version that matches your system (e.g., Windows 64-bit). 2. Update System Environment Variables
After installation, reboot your computer.
: Check your app.config or project settings to ensure there isn't a version mismatch or "remapping" error.
The mclmcrrt9-9.dll file is not a mysterious virus or a broken Windows component. It is a legitimate, essential part of the MATLAB Compiler Runtime version 9.9 (MATLAB R2020b). Errors related to this file almost always indicate a missing, corrupt, or mismatched MCR installation.
Because this DLL is a dependency, when it goes missing or becomes corrupted, the application that relies on it will fail to launch. Here are the most frequent error messages users encounter:
If it’s missing, add it manually and restart your application or computer. 3. Verify Application Configuration
If your compiled MATLAB application is 64-bit, it requires the 64-bit version of mclmcrrt9-9.dll . Conversely, a 32-bit app requires the 32-bit MCR. Mixing these causes cryptic “Bad Image” or “0xc000007b” errors.