During developing I often use SVN as CVS. However, sometimes when trying to commit I get an error message stating that a specific folder/file is no working copy which leads to a failure of the commit process.

But don't worry: it is easy to fix in a few steps:

  1. Create a copy of the affected folder and move it to somewhere outside your working copy.
  2. Clear the copied folder of all SVN-references (e.g by deleting all .svn folders).
  3. SVN-delete the affected folder (either be SVN CLI or from the context-menu when using tools like Tortoise/Rabbit-SVN) - if the folder contains subfolders make sure to also SVN-delete these as the SVN-delete command is not recursive.
  4. Commit the deleted (and only the deleted!) folder.
  5. Delete the folder from the filesystem.
  6. Copy the aforementioned copied folder back into the working copy.
  7. SVN-add the folder.
  8. Commit.
That should make sure, that you're working copy is usable again. Another way would be to just SVN-revert the folder to the last revision, but thus you would loose all changes you've made since the last commit/update.