Running excel on my mac with Catalina, I have split pages upside down and text mirrored.

Tim Doman wrote:

When I update it the update box opens and closes straight away so I cant.?

Big Sur—Microsoft 365 for Mac apps that run natively on Macs with M1.

https://www.microsoft.com/en-us/microsoft-365/blog/2020/12/15/4-ways-microsoft-365-is-improving-the-experience-for-mac-users/

The current Office for Mac; Office 365 or Office 2019 (One-time purchase) are OK with Catalina/Big Sur

Big Sur compatibility—Microsoft recently announced that it was officially ending support for Office 2016 for Mac on October 13, 2020. Apple Silicon compatibility in Office 2016 is questionable. Office 2019 no issues.

How do I upgrade Office?

https://support.office.com/en-us/article/how-do-i-upgrade-office-ee68f6cf-422f-464a-82ec-385f65391350

I remember this from a while back. You need to update excel.

Maybe a question for the Microsoft Help Community as to why you can't update:

In addition to what Bob said: what version of Excel is this?