Hello,

I want to search several open files and list those files which don't match the search term.

Like your other question, this can be only done with a macro. The macro searches in every file for the term and closes all files which has the term. After macro execution only the files are opened which do not have the search term. You should save all files before the macro is executed. All files must be real files (not buffers) with a file name.

InsertMode
ColumnModeOff
HexOff
Loop
IfNameIs ""
ExitMacro
EndIf
Top
Find "your search"
IfFound
CloseFile
Else
"ThisIsTheFirstFileWithoutTheSearchString"
ExitLoop
EndIf
EndLoop
Loop
NextWindow
Top
Find MatchCase "ThisIsTheFirstFileWithoutTheSearchString"
IfFound
Delete
ExitMacro
Else
Find "your search"
IfFound
CloseFile
Else
NextWindow
EndIf
EndIf
EndLoop

And again don't forget to enable the macro property Continue if a Find with Replace not found.