Getting "not enough memory" error on Painter 2017

When I click on some brushes I suddenly get the "Not Enough memory...." error and I have to hold down Esc forever to get out of it.  Everything in Painter, except the mouse pointer, is locked up.   I have 16 GB of RAM and the allocation to painter is over 11 GB while looking at Task manager shows that nowhere near that is being used.   I have it set to use 5 of the 6 CPU cores as well on my Windows 10 PC.  Everything else works ok.

I have had this happen when adjusting some settings on a few brushes (Particle brushes I think).  I'm certain this is a bug, has anyone else has this problem?   Any solutions?

Ron