Memory leak with Explorer.exe in Videos folder.

Memory leak with Explorer.exe in Videos folder with thumbnails enabled. Using Resource Monitor, I can see that explorer.exe is reading the video files, while memory increases steadily until it is 99%. No such memory leak problems when i set the layout as "list" (i.e. no thumbnails). Disabling thumbnails also eliminates the memory leak problem, but that is not what I want.  Videos folder consists of mainly .MKV files, with the video codec within the MKV container being H.264 high profile. I have tried to disassociate all media files with Media Player Classic Home Theater (which i use to watch mkv videos).

Most importantly, this problem only seems to have appeared after i installed SP1.

Win7 x64 Ultimate SP1, C2D E8500, 8GB RAM, Western Digital 2TB Green Caviar.

More info: I realized that this only happens with video files that have no thumbnail generated. It's as though Windows Explorer is reading through the entire video file to generate a thumbnail, but even after a long time it still doesn't generate a thumbnail.

How to fix? HELP!!!! THANKS!