@Jay.f updated windows? trying to plot to a network drive or local drive? if network drive directly (i have never tried that before) try plotting locally and moving it.. thats really the only other thing i can think of..besides asking you to post system specs for someone smarter than me who can help..
@xmagmax First I must say I'm not an expert, second different PC would have diffrent setting depend on devices it have.
Now that been said, to me your setting is a bit odd. Youe first value, which is 1, is the platform number that start from 0, 1 ,2 and so on. Normally it should be 0 because we only have 1 platform, at least mine is. The second value is the open GL device number, which also start from 0, 1 ,2 and so on. Open GL device would include all the CPU and GPU you have in your system, depend on the machine. You have to use bat file with "gpuPlotGenerator setup" command to check and decide which device you're going to use. gpuPlotGenerator setup command also tell you the rest value, but bare in mine these value are the potential max value your machine can handle. If, when plot and gpuPlotGenerator crash, you have to reduce these value (by haft).
In my case, I use RX480 8GB VRAM to plot. My setting values are 0 0 8096 32 4096 (my GPU is devidce 0, and my PC has 16 GB of RAM). I was able to plot 10TB Seagate int.HDD SATA3 in around 30Hrs, 8TB WD ext.HDD USB3 in around 26hrs, all in direct mode. But 8TB Seagate Backup plus HUB ext.HDD USB3 is an odd ball for me. Even with same setting, it took me over 5days to finish, don't know why.
So what I do to speed things up and reduce the chance of PC crash before finish plotting is to split in to smaller plot. I plot a 1GB plot onto a 1GB SSD then copy to the actual mining HDD, one at the time until finish the whole HDD.