Acronis True Image costs performance when not used

Summary

Over two years ago I installed Acronis True Image for Crucial in order to migrate my data to a new SSD I had just purchased. It worked. I then left True Image installed “just in case”, and what harm could that possibly cause. Well, funny you should ask. I recently noticed that whenever I plugged or unplugged my external monitor Explorer.exe would consume a lot of CPU time – dozens of seconds of it. It was enough CPU time to make my computer noticeably sluggish until things calmed down which could take 15+ seconds. “That’s odd” is how most of my investigative reporting starts so I grabbed an ETW trace and drilled in. It didn’t take long to find the culprit. Aside: I have worked with Acronis to help them understand this issue and they have provided a mitigation and have said that they plan to address the problem in the next release of their software. See “Workarounds and fixes” for details. In the trace Explorer.exe was using 44 s of CPU time over a 16 s time period (from 7.0 s to 23.0 s in the trace) which is way too much: I opened up CPU Usage (Sampled) to investigate. The CPU usage was distributed across dozens of unnamed threads so I hid the Thread ID column and the Thread Name column in order to group all the threads together and drilled down: I quickly found that windows.storage.dll!CFSFolder::_GetOverlayInfo was consuming a large chunk of the time (20,191 of the 42,299 samples), and most of that was in a call to an unknown function in tishell64_26_0_39450.dll. I temporarily ignored the question of who owned that DLL while I first tried to understand what it was doing. If you want to follow along you can download the trace I’m looking at and load it into Microsoft’s Windows Performance Analyzer (WPA). The CPU Usage (Sampled) data works by interrupting all running CPUs 1,000 times a second (by default) and grabbing call stacks. This makes it a powerful tool for understanding where CPU time is being spent. You can read more about how to use this information in Xpe...