target processor: not responding

I am having the same issue. Here's what I discovered and, hopefully, I'm right AND it will soon be resolved.

When you start with a fresh download, everything works fine, but if you did a little deeper into the Analysis and Synthesis Messages you may find a string of lines that reads,

"Warning: Messages from megafunction that supports OpenCore Plus feature

"+ Warning: Messages from megafunction that supports OpenCore Plus feature Nios II Processor

" + Warning: The reset input will be asserted when the evaluation time expires

"Warning: Megafunction that supports OpenCore Plus feature will stop functioning in 1 hour after device is programmed"

After that hour, you can download your Quartus sof file, albiet, time limited. After the hour expores, you'll get

Using cable "ByteBlasterII [LPT1]", device 1, instance 0x00

Pausing target processor: not responding.

Resetting and trying again: FAILED

Leaving target processor paused

Eventually, if you keep recompiling Quartus, SOPC and NIOS IDE projects, you'll find you get an error relating to a mismatch in the read versus expected sysid and timestamp values.

If you get here...STOP...you're just spinning your wheels!

Call and submit an Altera mySupport SR! I certain it's license related

Chris