title: Project explorer becomes empty in Eclipse
body: <p>Suddenly my <code>Project Explorer</code> becomes empty after restart:
  <a href="https://i.stack.imgur.com/cvEu1.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/cvEu1.png" alt="enter image description here"></a></p>
  
  <p>While <code>C/C++ Project explorer</code> shows projects:
  <a href="https://i.stack.imgur.com/whtAF.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/whtAF.png" alt="enter image description here"></a></p>
  
  <p>Where projects in <code>Project explorer</code> are gone and how to get them back?</p>