Desk opening

[447Debbie]

I basically created the top cabinet by copying the bottom one and making some changes from a door to drawers.  All was good, then I flipped the desk left to right and I end up with a board at the bottom of the opening.  How do I get rid of this?  It's a desk, there will be floor there, not part of a cabinet.  See area in red rectangle.  That's what I want to eliminate. 

[solver]

Don't know why.

 

Use 2 cabinets and a partition.

 

Use what you have but make the cabinet 1" taller, then position it -1" to the finished floor.