#include <MsgBoxConstants.au3> ; to declare the Constants of MsgBox
Local $sRegex = "(?m)-\d{4}-\d{2}-\d{2}.*$"
Local $sString = "GN1RLWFH0546-2020-04-10-18-09-52-563945.txt" & @CRLF & _
"JOHN-DOE-2020-04-10-18-09-52-563946t64.txt" & @CRLF & _
"DESKTOP-OHK45JO-2020-04-09-02-27-11-451975.txt"
Local $sSubst = ""
Local $sResult = StringRegExpReplace($sString, $sRegex, $sSubst)
MsgBox($MB_SYSTEMMODAL, "Result", $sResult)
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for AutoIt, please visit: https://www.autoitscript.com/autoit3/docs/functions/StringRegExp.htm