Same problem here. Using PDF preview through the OS (el Capitan)

iMac i7 with 24 GB RAM, AMD Radeon HD 6970 2048 MB graphics card.

Recently switched from Mountain Lion to El Capitan and at the same time bought ACAD 2016LT to replace 2012LT we were using on Mountain Lion.

I always print to PDF and it takes anywhere from 3-7 minutes now watching the spinning beach ball. It doesn't seem to matter if the drawings are more complex, nor the size of the sheet. Everything is 2D, and often the sheets are 11x17. Never larger than 24x36.

Overall, Autocad LT 2016 runs somewhat slower, but I've been giving it a few weeks to get used to things.

Any ideas? Thanks in advance!