在解决构建路径错误之前无法构建项目（仍然）

Question

Every time I try to build (doing a full Clean and then build afterward) I get this error message popping up under Eclipse's Problems section. The project itself also shows an error beside it.

I've tried everything contained in the other solutions to this exact same question:

1. Removing all libraries in project properties and re-adding them
2. Manually edit project.properties file, .classpath file, etc.
3. Performing full Clean and then build afterward

This stubborn error message won't go away. The problem is that the error doesn't tell me anything about what's messing up. The Location says "Unknown", and that's all I have to go on. No errors appear under any of the Build Path tabs. Everything looks fine.

What the heck is going on?!

UPDATE: Here's a screenshot of the 'Problems' tab:

Answer 1

Look under 'Markers' tab, do you see any java build path issues there? Sometimes it complains about not having src/test/resources or other directories.

Answer 2

Restart Eclipse. It works for me!
You can also check with a new clean workspace if the above didn't work