I recently upgraded from VisualSVN server 1.7.1 to 2.0.5. After the upgrade, we started to get random warnings similar to the following when doing an update using the CollabNet 1.6.5 command line client: (Note: I removed specifics about our repositories in the warnings below for security reasons)
svn: warning: Error handling externals definition for 'projects09\path here.....: svn: warning: Server sent unexpected return value (500 Internal Server Error) in response to OPTIONS request for 'http://repos URL here' OR svn: warning: Error handling externals definition for 'projects09\path here.....': svn: warning: Server sent unexpected return value (500 Internal Server Error) in response to OPTIONS request for 'http://repos URL here' The warning is not specific to a particular URL and occurs with different repositories as well. If we immediately rerun the update, it will frequently function as expected. I tried an upgrade to VisualSVN server 2.0.6 and the problem still occurs.