After reinstalling my system, I’ve consistently been missing a decent PDF reader. Within the 360 Software Center, I saw Xundu PDF recommended, even with a “special edition.” I had already formed a slight impression of this brand at that point, wondering how a niche software like a PDF reader could possibly generate profits – surely the promotional costs wouldn’t pay off. Later, I encountered it again through Xunlei’s promotion, and my computer did indeed need one, so I conveniently installed it.

Everything was fine… until the weekend…

After installing the software, it worked perfectly without issue. I noticed some AI features within it, but they required a paid subscription – which wasn’t useful for me, so I didn’t purchase them. Back then, I naively thought, “How much money could those paid features really earn?”

Until this weekend, when QQmusic suddenly and inexplicably froze and crashed while I was developing locally. Instinctively, I opened Task Manager to see if there were any lingering processes. I discovered that the QQmusic process was still running but unresponsive, so after forcibly ending it, QQmusic could start up normally again.

However, I inadvertently discovered a process named “PDF Engine,” which was consuming nearly 10% of CPU usage – while the entire system’s resource utilization was only 19%. Curious, I checked the file path and found that it was actually my previously installed Xoon PDF!

Loss of Trust

I don’t know if this is a defect in the software, but I’ve completely lost trust in it at this point. Considering its widespread promotion, I can’t help but wonder where all those high promotional costs are coming from – they must be earned somehow. The clandestine running of strange tasks in the background seems almost “reasonable” in retrospect.