Vanishing task bars

Hi, 

I know how to get the task bar back and it's not being auto-hidden... 

I have a Del M6800 running Win10 connected to an E Port plus replicator and two Dell U2412 monitors. With about 10 minutes of booting up the task bar on the main laptop screen disappears, the background image shrinks to the top left and the later on the task bar on the U2412 monitors vanishes. 

I have tried two different port replicators - same issue. 

Anyone have this problem before and know of a permanent solution? 

Thanks