SVN externals repo "is already locked" on update

Question

Basically I have to repo on the same server:

svn://repo/foo
-> checked out to d:\foo

svn://repo/bar
-> d:\foo has an svn:external property set to check this out into d:\foo\bar

When an "svn:update" or a new "svn:checkout" this is gist of the error:

Command - Update
Updated - D:\foo
External - D:\foo\bar
External failed - D:\foo\bar
Error - d:\foo\bar is already locked via d:\foo

After I "clean" or manually release the lock, the problem still persists.

Any insights would be greatly appreciated. Thanks!

Update:

Attila nailed it in the comment. I had "foo/bar" existing in the repository.

For future reference - when using SVN:External property, SVN will create the destination folder for the external reference.

Answer 1

As resolved in the comments (just to have it in proper answer as well):

When using svn:externals, the directory where the externals repository is checked out should not exist in the original repository