I use a Mac and have had no issues with Blender, but I do not make clothing mesh. IIt could be you do need Avastar, but I do not know. Contact one of the In-World Blender groups like the JASS group, perhaps they can help you.
Avastar is a paid add-on for Blender you can purchase In-World or at Gaia Clary's website http://blog.machinimatrix.org/ You can also find lots of information and tutorials there for making mesh and sculpts.
Morgaine Christensen
Hell House Design
"What we have to learn to do, we learn by doing."-- Aristotle
"One must learn by doing the thing; for though you think you know it, you have no certainty, until you try.-- Sophocles
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