Trying to run Turbo tax 22, and it says I have OS 10.15.7 Catalina, and I need to have OS 10.16 Big Sur, but my iMac software says I up to date and when downloading Big Sur, it says not available

..joeyzone190_1..

Perhaps should you identify your build year iMac, others may

see where it might or not have an issue with the system on

board; could be it might be at the end of its update path; &/

or has no further upgrade, there?

Identify your iMac model - Apple Support

//support.apple.com/en-us/HT201634

Several ways to get a new downloadable installer exist;

while some may only be whatever version is there now.

How to download macOS - Apple Support

About background updates in macOS - Apple Support

If an error occurred while updating or installing macOS - Apple Support

[TurboTax relies on their upgrade path to sell customers latest versions

& appears to force marginal systems into obsoletism where applicable]

All is not lost 😀

If the user wishes to explore the Apple Trading In option where the Value of the exiting machine could be used against the cost of a new Apple Computer 

Or Shop Refurbished Apple computers at an Apple Reduced Cost

Have used both previously and have been satisfied each time.

..joeyzone190_1..

Through the recent/past holiday season, several fair offers from resellers

such as OWC online (by email) were enticing. While none of my Macs are

adequate to support any of these commercial tax preparation softwares.

A recent portable Mac or one which shipped with Catalina, should support

at least Big Sur. Some offers go on throughout the year.. Every few weeks.

https://eshop.macsales.com/Service/ (ask for ideas without purchase)

TurboTax 2022 requires macOS Big Sur (11) or later. It is not compatible with Catalina.

If you have Catalina 10.15.17 you could still use the online version of TurboTax.

As an alternative, the H&R Block Tax app runs on Catalina.