yes - I can't expect it was related to ZPM, but definitely seemed that way when it was the only image that didn't work in that state. 

Warning I guess for others reading this thread:  

docker system prune -f

Did remove 3 containers I had created, run and stopped on my system (but was planning to get back to them and start them again).  

thanks for now..

well that sucks.... 

docker system prune -f
Deleted Containers:
98a246148a9bbe5dd84ca435368dcc072173660320c7b3198788d135bb4a17bb
d53fcde88168b084928bda0a95daecfa08661efcdf5e04b875e75b9c45f373c1
54e4d30989a7b94a828d8e554acf6ad6caa9ca74928b28db011bfc30148cfe68
42f1432d7f62bbd0b6a9f8c4dc6e1e74fb9d6717c3c45b8a53d4228506cf4599

then re-running .. worked...

That may seem a great outcome to some, but, this un-predictability or, failure to report what the issue is (remember, the issue manifested in an IRIS process hanging), is not ideal. 

Also - I did try with non-ZPM containers successfully multiple times, whilst I was getting the issue, just to ensure, the issue was with only the zpm ones. It worked fine every time with non-ZPM containers.

Steve

yes