File size monitor - how to ?

File size monitor - how to ?

Hi ALL!
I need monitoring size of Windows Log Files (Security.evtx + System.evtx + Application.evtx)
I created (and associated) 2 custom File Monitors and setup "File Path"  field:
a) C:\Windows\System32\winevt\Logs\Security.evtx
b) %SystemRoot%\System32\Winevt\Logs\Security.evtx

but when i tried test this Monitors i have error - File not found 
Why?
How it works ??

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