There is use the beforeupdate event, and code something like this:
Code:
dim checks as integer
checks=0
if [checkbox1]=true then
checks=checks+1
endif
if [checkbox2]=true then
checks=checks+1
endif
if [checkbox3]=true then
checks=checks+1
endif
if [checkbox4]=true then
checks=checks+1
endif
if [checkbox5]=true then
checks=checks+1
endif
if [checkbox6]=true then
checks=checks+1
endif
if [checkbox7]=true then
checks=checks+1
endif
if [checkbox8]=true then
checks=checks+1
endif
if [checkbox9]=true then
checks=checks+1
endif
if [checkbox10]=true then
checks=checks+1
endif
if checks<3 then
me.cancel=true
msgbox "you must select at least 3 checks to continue"
endif