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ZSpheres adaptive skin preview crashes program

I blocked out a tree shape using ZSpheres, and when I press ‘A’ to get a preview of the adaptive skin, it crashes the program.
This only happens if the Dynamesh resolution is set to 256 or higher, and it never happens at 240 and below.
The polycount for the resulting skin is 448K at 224 resolution, and 514K at 240 resolution. But at 256 resolution the program crashes? I thought I could go up to a polycount of 20 million?
Is this an inherent problem with ZBrushCore vs, ZBrush?
I have 16GB of RAM and according to ZBC I have over 10GB free. Is this not enough memory?
I would attach the file but the forum won’t allow .zpr files. That seems incredibly counterproductive.

Update: I tried another ZSphere creation, only 2 parent spheres and around 20 children.
At a resolution of 560, the adaptive skin was successfully created with a polycount of 1.9MP
at a resolution of 576, the adaptive skin crashed the program.

Update: After a reinstall of the program, it seems to work better. Polycounts above 3M and no crashing. Hope it lasts.