Mesh reduction error v5

Hello all,
I’ve been dealing with reducemesh failures for a couple of years and just never got around to addressing it here.
“Could not complete mesh reduction. Try decreasing your reduction percentage or increasing your final face count.”

I usually get this error on dense meshes, but it can happen with smaller meshes as well. The current case is with 6M+ tricount meshes, using any percentage reduction on fast setting and I keep getting this error. Doesn’t matter if I only try reducing by 1 poly. These meshes are closed and watertight.

Does anyone have any ideas for dealing with this error in v5, or is this just a bug that is unfixable at this point?

I have not tried these in v6 yet, I’m keeping my office on v5 until more issues are smoothed out with v6.
Looking for Rhino v5 solutions. I currently take these into meshmixer to reduce when I get the error.

Thank you,