How to stop Excel from automatically checking Workbook performance?

This is the best description of the situation. Thank you for providing it!

Absolutely right. It is very annoying that MS is not capable to turn this whole force check OFF.

I think we might need to vote this up in the microsoft feedback channel too.
there are several, but here is one link. You can search excel channel for word "performance"

https://feedbackportal.microsoft.com/feedback/idea/52093f8d-fa00-ef11-a73d-6045bd7e894e

I think the idea behind the performance checking is great but typical of Microsoft, they do in a way that makes it virtually unusable and DO NOT let users turn it off which should be an option on all new features that interfere with general operation!!

The optimization has no idea how the spreadsheet is intended to be used and in so many cases the user has added extra formatting for a specific purpose, perhaps to mark pending changes or issues that need resolved - I personally use orange red and green to mark progress whilst making changes, items that need changing or are in progress and red for areas to delete. I usually mark these in Column A. The optimizer thinks these should be removed as they are excessive formatting!!

I am now building almost exclusively with dynamic arrays and have set formatting to allow for he expansion of these arrays so that they are formatted. The optimizer thinks these should be cleaned which means when the values change and the arrays spill, they will be un-formatted!!

Finally, when reviewing the suggestions made by the optimizer, it actually tells you which ranges need to be optimized. Great. But why not when I click on this range can it not highlight it on the sheet and then let me choose to optimize that particular range or mark it to be ignored. That would be really useful. But no, I have to do all the optimization or none. I can't choose selectively thus rendering the tool completely useless!!

Come on Excel team. You have created a great product and the dynamic arrays are awesome - don't wreck it by introducing half built tools (I'm being polite here as I do not think the intention was to make them better but I live in hope) and then forcing them on users!!

Listen to the users. Add a checkbox to allow this to be disabled - and preferably from a link on the optimization ribbon so that users then don't have to hunt around the options looking - eg "Disable further optimization checking on this file". And perhaps when the optimizer is more useful by enabling selective optimizations, more people will use it. As it is, who is going to risk giving it carte blanche to wreck a model!!

Prash, thanks for your response.

I have a question:

• What counts as "Excessive" and what counts as "Unintended"?
  • Every cell in a workbook contains some formatting.
  • There's a font (with all its associated subsettings like bold, underline, strikethrough, etc), a data type, a cell color (even if it contains no color that is still a choice that must be stored in some way).
  • So why does changing, say, the Date format or the Font or even the color count as formatting more than the default settings?
• ...Is it perhaps because Excel only stores exceptions to the default settings?

... and a couple comments on some fundamentally flawed thinking behind this "helpful" feature:

• I have used that optimizer and it absolutely trashed my workbook. I did not expect that. I had to close quickly without saving and revert to the last saved version. It shocked me how bad my workbook looked.
• You (MSFT) are optimizing on speed alone but ignoring a million other human factors that you know nothing about.
  • The workbook may gain a few milliseconds - or even whole seconds - in raw speed but at the expense of ruining the entire usability of the workbook
  • This can actually decrease performance of the people and organizations using the workbook in ways you cannot track or understand and which will almost never be reported
  • So when we design these workbooks, WE the Users decide whether our changes are worth the performance hit
  • ...and the performance hit is often measure in milliseconds or, at worst, seconds anyway
• It is not up to MSFT to decide for the user what is "Excessive" or "Unintended"
  • 'Excess' and 'Intent' vary almost infinitely by user and use case

I do look forward to being able to disable the performance checking at the user level and also at the workbook level. That is to say I don't want to disable performance checking on MY machine/instance only to send my hard work to someone else and have them performance check it into oblivion by mistake.