Yamn is temp place holder element
C:\Pylo\MCreator179\forge\build\sources\main\java\mod\mcreator\modname.java:35: error: cannot find symbol
mcreator_yaMN mcreator_0 = new mcreator_yaMN();
^
symbol: class mcreator_yaMN
location: class modname
1 error
FAILURE: Build failed with an exception.
* What went wrong:
Execution failed for task ':compileJava'.
> Compilation failed; see the compiler error output for details.
* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.
Just select another workspace and then the first workspace again in MCreator. This should will this bug. MCreator 1.8.0 won't have this bug anymore.