Formula speed / Laptop specification

Thank you NikolinoDE there is a lot to go through there but I will and I will feed back to you.

I am absolutely blown away by how helpful everyone here has been.  I really didn't expect so many replies.  Lots for me to review and try out and investigate.

I will certainly share the hardware spec with my manager to see what she can do for me.  In the meantime I will make a start on reviewing my master workbooks to see where I can follow all the tips and cut out any unnecessary tasks for excel to do.  I've promised to share with my colleagues to as there are other in my team having similar problems.

I will go through your list item by item and make a note of any improvements.  Though it may take me a week or two because i'll have to do it all in between work but there will be opportunities as I am going along.

Thank you so much for taking the time to share.  I've struggled for two years and there have been tears and tantrums along the way so I am excited to get a bit of control back.

Allison 

NikolinoDE 

I have found that Microsoft broke the Worksheet calculation in 64bit versions later than 1902.  Stay away from xlCalculationAutomatic in newer versions of Excel you have large spreadsheets or spreadsheets in which cells are periodically changed.   You must turn off calculation (Application.Calculation = xlCalculationManual) an fire the calculation of sheet only when you need to otherwise risk the total crash of Excel.   I have spent a considerable amount of time and headache, including a ticket with Microsoft until I finally found that Microsoft updates specifically 2012 and 2101 have been totally screwed up!

I have about 15 spreadsheet VBA applications running at customer facilities that poll and populate sheets with operational data through a Modbus communication active X (MBAXP), all running anywhere between versions 1708 to 1902, these applications running flawlessly for weeks on end no problem whatsoever.  Then the last two applications I ran into a huge problem.  The same application would hang as soon as it started, I couldn't select any cell it would run for about 10 minutes then the darn Excel would crash and restart with recovered versions of the same application, the recovered application having no difference.  I originally thought it was a computer problem until I started experimenting with other versions Excel!  I downgraded to earlier versions and found that all was good, polling selecting was normal.  Then I experimented with the newer version, specifically 2012, thinking it could be the MBAXP.  After replacing the MBAXP with a timer and a random number generated sheet populating macro I found that the hangup was the sheet calculation, timing the difference between 2012 (2101 was a little better) and the version 1902 at sometimes over 50 times as long in the new versions!!  I had to limit the timer for - again - after about 10 minutes the darn Excel would totally crash and restart. No one at Microsoft (or anywhere else) seems to know why there is such a huge loss in calculation speed.  I can only guess the programmers at Microsoft don't know what they are doing.  While I finally solve the mystery, I am left to wonder whether Microsoft is intent on screwing up the product, leaving me to consider alternatives.  Its quite a bummer.   BTW the following link is a step by step instruction on downgrading to a working Excel version.  Try v1902 it works.  https://answers.microsoft.com/en-us/msoffice/forum/msoffice_install-mso_win10-mso_o365b/revert-to-a-previous-version-of-office-365/79138c95-80b4-48fb-bef7-08619af3593e