Are you sure about that ?

Right click the "CFD Basic Info" tab and select View Code.
Insert the word STOP as the first line in the Worksheet_Change sub.
Go back to the "CFD Basic Info" sheet and click a hyperlink to view that sheet.
Note the User number.
Go back to the "CFD Basic Info" sheet and change the User for that hyperlink.
The code will stop and display itself with the STOP line highlighted.
Use the F8 key to step through the code one line at a time and see what happens.
When the sub finishes, check that hyperlinked sheet again for the User.



Before removing the STOP instruction, try inserting a line for another Ser No.
(do this near the top of the Ser No. list so you're not looping too often while doing things manually)
and use F8 again to see what happens and where the code goes.

Hope this helps to explain and show what's going on.