Create a .zip, clearing the archive attribute of each file zipped (i.e. Incremental Backup).

Download Chilkat 32-bit Zip ActiveX (.msi) (includes objects for .zip, .gz, .bz2, and .Z)

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How to create a .zip archive such that each file zipped will have it's archive file attribute cleared.

LOCAL loZip
LOCAL lnSuccess
LOCAL lnRecurse
LOCAL lnArchiveOnly
LOCAL lnIncludeHidden
LOCAL lnIncludeSystem
LOCAL lnSaveExtraPath

loZip = CreateObject('Chilkat.Zip2')

*  Any string unlocks the component for the 1st 30-days.
lnSuccess = loZip.UnlockComponent("Anything for 30-day trial")
IF (lnSuccess <> 1) THEN
    =MESSAGEBOX(loZip.LastErrorText)
    QUIT
ENDIF

lnSuccess = loZip.NewZip("test.zip")
IF (lnSuccess <> 1) THEN
    =MESSAGEBOX(loZip.LastErrorText)
    QUIT
ENDIF

*  Tell the component to clear each file's archive attribute
*  when zipping.
loZip.ClearArchiveAttribute = 1

*  Append a directory tree.
*  Notice that the archiveOnly flag is set to true.  This
*  means that only files with the "File is ready for archiving" bit
*  set will be included.  (In Windows Explorer, right-click a file
*  and select Properties.  Then click the Advanced button.  You'll
*  see the "File is ready for archiving" checkbox.
*  This becomes automatically checked whenever a file is modified (or created).
*  The AppendFilesEx method will only add files ready for
*  archiving, and the WriteZipAndClose method will clear the
*  archive attribute for each file zipped.  The result is that
*  each time you run this program, only the modified files are zipped.

lnRecurse = 1

lnArchiveOnly = 1

lnIncludeHidden = 1

lnIncludeSystem = 1

lnSaveExtraPath = 0
loZip.AppendFilesEx("c:/temp/abc123/*",lnRecurse,lnSaveExtraPath,lnArchiveOnly,lnIncludeHidden,lnIncludeSystem)

lnSuccess = loZip.WriteZipAndClose()
IF (lnSuccess <> 1) THEN
    =MESSAGEBOX(loZip.LastErrorText)
    QUIT
ENDIF

=MESSAGEBOX("Zip Created!")