I was having a few issues with FormZ quitting by itself on a large file since I installed the latest plugin (well I think since then!). Say I was working on the file and left the computer for a while, I would return to see that FormZ did a runner..
Also, quitting FormZ left it trying to quit but becoming unresponsive (have to force quit it).
So I removed the maxwell plugin and now all is well (so far!)..
The file is large at 128mb with tons of materials (maxwell), let me know if sending you the file will help..
Maybe my computer is running out of memory (only 8mb)
iMac 27", OSX 10.9.5, 3.4 GHz Intel Core i5