I have Quicken 2007 on a Mac. I just updated to OS Big Sur and 2007 is not supported on it. What p

I'd suggest you try the current Quicken Mac to see if it will meet your needs. There is no free trial, but you can purchase it and get a full refund within 30 days if you decide to to go forward with it.

As you may know, when former parent company Intuit halted development of Quicken Mac in 2007 because the technology was too old to continue to update, they embarked on a path to re-build Quicken as a modern Mac application. There's a decade-long tale of missteps and false starts, multiple management turnovers, changes of direction and eventually Quicken becoming independent of Intuit. Today's Quicken Mac has much of the functionality of its predecessor, but the developers are still building out features users have asked for which are missing from Quicken 2007. Most longtime Quicken 2007 users (myself included) have successfully made the transition to the modern Quicken Mac, but a small minority continue using Quicken 2007 for specific features, despite the shortcomings of the old database and the workarounds necessary to run in on modern Macs.

In my opinion, the option to install Virtual Machine software and install an older Mac operating system within it in order to run Quicken 2007, as smayer97 mentions above, should be an option you consider only if you have evaluated and determined that the current Quicken Mac does not meet your needs for some reason(s). Running the 15 year-old software in a VM is a workaround which works for some users, but it carries some risks and delays an inevitable need to move forward. Quicken Mac is supported should you need help, it converts Quicken 2007 data files, it runs on a modern database which is not prone to corruption like the old Quicken 2007 database, and it offers a full range of online connectivity should you wish to download transactions or pay bills online with it. The software is updated every few months with new features and bug fixes.

The overall user interface of Quicken Mac is quite different from Quicken 2007, and most people making the transition have an immediate knee-jerk reaction that they don't like it because they're so used to the old interface and operation. There's a bit of a learning curve and it takes some time to get used to the new way of doing things, but I found that once my brain adapted, I was generally happy with the new version. There are some features I miss from Quicken 2007 that are still on the developers' to-do list, but for me, they are not 'show-stopper' issues. Because we all use Quicken and its features so differently, only you can determine if the same is true for you.

And, of course, another adjustment is that you have to pay for Quicken Mac, which is sold as an annual subscription.  Quicken 2007 users were fortunate to be able to use the software at no cost for more than a decade, but there's ultimately no free lunch, and user fees are what pay for the continued development of Quicken Mac.

@“Max Mandelis”  The old Quicken icon has a slash through it because macOS knows it is an old 32-bit program which cannot run on Big Sur, which requires programs to be 64-bit.