SVN: Folder already under version control but not comitting?

I had a similar-looking problem after adding a directory tree which contained .svn directories (because it was an svn:external in its source environment): svn status told me "?", but when trying to add it, it was "already under version control".

Since no other versioned directories were present, I did

find . -mindepth 2 -name '.svn' -exec rm -rf '{}' \;

to remove the wrong .svn directories; after doing this, I was able to add the new directory.

Note:

• If other versioned directories are contained, the find expression must be changed to be more specific
• If unsure, first omit the "-exec ..." part to see what would be deleted

Copy problematic folder into some backup directory and remove it from your SVN working directory. Remember to delete all .svn hidden directories from the copied folder.

Now update your project, clean-up and commit what has left. Now move your folder back to working directory, add it and commit. Most of the time this workaround works, it seems that basically SVN got confused...

Update: quoting comment by @Mark:

Didn't need to move the folder around, just deleting the .svn folder and then svn-adding it worked.