In PowerDirector 15 (Windows 10, 4 i5-6500 cores, 16GB RAM), I took about a month break from editing a project. The project is nothing fancy - just pictures, music and text fading in and out. Despite its simplicity, when I push spacebar to preview anywhere in the project, it renders so slowly that I literally see nothing and only hear the audio. This issue wasn't present a month ago.

In fact, even when I merely single-click on the timeline just to view a single frozen frame of the project, it often takes 15-20 seconds to "render" in the preview window even though it's just a stupid little JPEG.

(Side note: after the previewing is done, a little green bar appears literally on the timeline grid, permanently marking that spot in the timeline, perhaps to show me that "this is a slow spot to view" for future reference, similar to the yellow and red routes on GPS... but that's just my guess.)

In my NVIDIA control panel, I tried setting "CUDA - GPU" to "none" for CyberLink PowerDirector. I even restarted PowerDirector... didn't help.

The only "change" I made to my system since then was the installation of Presonus Studio 1 v.3. (Not really a system change, just a new application.)

Help please!