>>I have a backup menu dan the client can create his own backup filename.

I think NUL is missing from the list of no-nos.

>This is what we use, is was from Chris Lange I think
>

>********************************************************************
>FUNCTION lValidFileName( tcFileName )
>********************************************************************
>  LOCAL lcValidChars, lcUpperJustFileName
>
>  m.lcValidChars        = " ^'@{}[],=()+._-!$%&/#~1234567890ABCEDFGHIJKLMONPQRSTUVWXYZ"
>  m.lcUpperJustFileName = UPPER( JUSTFNAME(m.tcFileName) )
>
>    DO CASE
>	CASE EMPTY( m.lcUpperJustFileName )
>		RETURN .F.
>	CASE INLIST( JUSTSTEM(m.lcUpperJustFileName), "AUX", "COM1", "COM2", "COM3", "COM4", "CON", "LPT1", "PRN" ) 
>		RETURN .F.
>	CASE LEN( CHRTRAN( m.lcUpperJustFileName, m.lcValidChars, "" ) ) > 0
>		RETURN .F.
>	OTHERWISE
>		RETURN .T.
>    ENDCASE
>
>ENDFUNC 
>