Generate Near Table tool not finishing on single feature

I am trying to use the Generate Near Table tool to find the nearest polygon (within 50 metres) from points. If I run on the entire points feature class the Generate Near Table tool produces the expected output, same as if I select multiple points.


However, if I select a single point, the Generate Near Table tool never finishes (it takes seconds on the entire point dataset)


I'm running ArcGIS Desktop 10.1 Advanced SP1. This happens when used within ArcMap on layers, or from ArcCatalog using the feature classes themselves.


I'd appreciate any help on how to get this working, as I would like to add this to a script, but at the moment I'm having to make sure there's a count > 1 for it to work.

EDIT: A bit more information - The two feature classes (point and polygon) are in SDE (9.3.1 I think). If I put them both into a File geodatabase, the tool runs as expected. If I put the polygon FC in the file geodatabase and leave the point FC in SDE the tool runs as expected. However, if I put the point FC in the file geodatabase and leave the polygon FC in SDE the tool doesn't finish.
This ONLY happens when a single feature is selected. If multiple features selected, or tool run on all features, the tool completes successfully.

Thanks,
Mike.