Using VBA to track changes in Excel - Suggestions? -

i have large number of workbooks (~4500), each 4 sheets, need able track changes in. have following code:

private sub worksheet_change(byval target range)     application.screenupdating = false     vnew = target.value     vaddress = target.address     application.enableevents = false     application.undo     vold = target.value     if vold = ""         target.value = vnew         target.interior.colorindex = 6 'make whatever color want when used blank     elseif vold <> vnew         target.value = vnew         target.interior.color = rgb(146, 208, 80) 'make whatever color want when cell changed     end if     application.enableevents = true     application.screenupdating = true end sub 

unfortunately, buggy users trying copy , paste blocks of text , not ideal in stops ability use undo. have thought using conditional formatting having copy 4 sheets "*_old" sheets, or have compare to, doesn't seem feasible sheer number of workbooks have work with.

we can't use built in excel track changes due project needs. need cells highlighted.

does have recommendations or tried-and-true methods this?

btw, using python macros workbooks in large batches right now.