not only pagefile.sys was missing in C:
i also see a message about pagefile.sys overwrite had some error or thing like that, and it will turn back the size of pagefile set previously.
what i do current is just set VM to zero, the effect just let pagefile would be zero whenever the message pop
however, the message is still pop occasionally
before this issue, my Pagefile.sys was didn't exist in my PC. i once deleted it but i didn't remember when