Troubleshooting  

Problem
The compiler cannot find classes
Solution
Ensure the classes are on the classpath. You need to run update if you have declared managed dependencies. Unmanaged jars should go in lib/ by default.
Discussion
You can use console-project to list the contents of classpaths. Check that the expected jars exist and contain the classes you want. You can also use javap for this purpose.

A common cause is forgetting to run update. See the documentation on classpaths and managing dependencies for more information.

Problem
Corrupted download of sbt or Scala
Solution
Restart sbt after deleting:
  • ~/.m2/repository
  • ~/.ivy2/cache
  • project/boot
Discussion
While this should not normally be necessary assuming Ivy is doing its job properly, removing these directories will reset things to a clean state so you can be sure whatever problem isn't being caused by corrupt or stale cached files. If you find yourself doing this repeatedly, please report the issue.