- Try deleting all the "slprj" folders in the directory you are working.
- After deleting "slprj", try to build and see if this error happens again.
- If the issue persists, please check the directories for Simulink codegen and Simulink cache. You can find more information on those folders in the following link:
- Make sure that the settings indicate that the "slprj" folder (codegen) is created in your current project directory. If it is not, set it to the current directory and try to build.
- (If step 2 did not work) Try to set both the cache and and the codegen directories to be in the same folder and see if that helps you build.