xgen error Cant open ptex file

[Mr.baiking]

I've an error when rendering xgen

"Error:Can't open ptex file:Z:/xxxxxxx.ptx

Too many open files"

the error happen to all the description when it read ptx,and last arnold does render the xgen but looks wrong

I've tried render in katana and found that if set "maya_path" to maya2017 i got the same error like in maya,but if set to maya2018 ,the error just gone and xgen render correctly

So how to fix this in maya? I'm use maya2017 mto 2.1.0.3 win10 dual E5 cpu in production

Need your help