Is there a way to stop the check performance pop-up?

May I suggest that the simplest solution here is simply to disable the feature? I'm incredulous about the claims that making this feature optional is somehow beyond your technical abilities as a team / company. Unless you can show evidence of more users finding it useful than annoying / harmful, simply admit it wasn't a useful addition and remove it. I asked Chat GPT for a quick steer on this...

I asked: "microsoft have introduce a "Check Performance" feature into Excel which brings up a pop-up unhelpfully offering to remove what they describe as unnecessary formatting. There is no way to disable the notifications, meaning that end users may inadvertently wipe carefully constructed formatting from a sheet. Can you find evidence of anyone reporting that this is a useful and valued feature? How does this compare against the volume of complaints about this feature?"

The response: "The "Check Performance" feature in Excel, which identifies unnecessary formatting and metadata that could slow down large workbooks, has received mixed feedback. On the positive side, Microsoft promotes it as a tool that can help make workbooks more performant by removing redundant elements, particularly in cases of large, sluggish workbooks. However, it requires user intervention before making any changes, meaning it doesn't automatically alter your workbook without your consent.

The feature has not been widely embraced as a highly valued addition, with feedback indicating that it might be overly cautious and not always clear in its operations. For instance, the tool sometimes misses empty but formatted cells, and its detection logic can be inconsistent, which leads to some frustration among users who expect it to catch all unnecessary elements. The optimization suggestions can also sometimes change workbook formatting, which poses a risk to carefully constructed sheets​( TECHCOMMUNITY.MICROSOFT.COM

On the other hand, there is a notable volume of complaints, particularly about the lack of an option to disable the notifications. Users are concerned that they might inadvertently apply changes that disrupt carefully designed formatting. The feature’s limited documentation has also been highlighted as an issue, as it often leaves users unsure about what to expect from the tool and its impact on their workbooks​( Office Watch

Overall, while some users appreciate the feature’s intent, the general sentiment leans towards dissatisfaction due to its intrusive nature and the potential for unintended formatting changes."

The General Sentiment leans towards dissatisfaction. So are you making software to annoy people or in an attempt to provide useful service?

this is super annoying and risks formatting that I want to remain, and yet, now it at risk of being optimized every time this file is opened, by anyone in our company and creating lots of lost time to reformat. Software is suppose to get better, not worse over time. Stop trying to have so much predictive functioning and just get back to what the program was suppose to do.

Just started experiencing this issue, still can't find any details on how to disable this annoying "Feature"

Sadly there is no "disable" for this as Microsoft in their infinite wisdom thinks it doesn't need a fix and we would rather completely reformat out carefully crafted excel sheets to something resembling a 1995 bare bones excel spreadsheet than stare at the "warning". I've read somewhere where someone talked to a dev or a dev representative and it was said that it is just too hard to put a simple disable checkbox for the damned warning.

Sorry bub, you plain outa luck on this issue. Add your voice to choir and maybe Billy boy will hear us from way up on high.

I agree fully, I've scoured the network and can't seem to find a way to disable this "feature".

The "Performance" and "Backup" notifications are completely worthless and very annoying, especially for creators of worksheets that are distributed to others. I have yet to find one user of Excel that likes or wants this: "feature".

I guess we can only hope they don't start doing the same with advertisements imbedded within the applications we have already paid for, but they likely will.

Whoever thought this idea up should be fired.