Unfortunately those error messages are basically worthless. How full is the drive they are writing to? Try downloading GSmartControl and use it to test the drive for problems. It should offer a "short test" which takes a few minutes, and a "long test" which takes many hours but tests the drive more thoroughly. You can also just view the SMART data for the drive but this can be difficult to interpret.
The PC is used for BI only and the USB drive is my "New" folder only.
I've just had a look in the PC (Dell 9020 SFF with service tag BC9TG52) and there is a blue HDD caddy that has a 7mm SSD in it with space for another HDD. I'll have to workout what size fits and install it internally. Any thoughts?
The tests I did on the USB drive were all 100% OK. So it may just be related to delays in waking the drive up before writing (I'm just guessing here though).
I am not completely up to date on all the windows 10 changes. But if you are running windows 10. Microsoft changed the behavior of the USB and caching in a recent update. This may be adding to your problem.