Likewise, just happened for the first time ever. I was playing a 1080p youtube video, had Steam running and the momment i opened two Word files together my memory usage jumped to 99%, even to the point og using the main SSD drive space as virtual memory. Only a restart fixed the problem. Also i noticed that the process which caused this was named "Fuentes"; because my Windows is in Spanish, I checked that indeed the process is "SearchApp.exe", the one that caused the memory leak.
Specs:
Windows 10 Pro
Intel Core i7-7700K
32GB RAM
256GB SSD System
2TB HDD + 2TB HDD + 1TB SSD
Nvidia GTX 1080 (DCH 511.79 drivers installed)