Hi there, @Kathryn130962.
Thank you for providing additional details about your concern. As my colleague @FritzF mentioned, this is caused by the incompatibility of your operating system and your QuickBooks Desktop version. To update to the latest version, here's how:
- Sign in to Windows as an admin user.
- Download the latest version of QuickBooks, then follow the on-screen instructions to install it.
- Once done, open the newly installed QBDT and click Open or Restore Company or go to the File menu and pick Open or Restore Company.
- Tick the Open a company file and click Next.
- Locate the company file, then choose Open.
- Log in as admin and hit Update Now to start the upgrade.
- Once finished, select Done.
You can check out this article if you're using a subscription version to know how to upgrade: Upgrade to newer versions of QuickBooks Desktop Pro Plus, Premier Plus, or Enterprise.
If you're still not able to open your company file, you can follow the troubleshooting steps in this article: QuickBooks Desktop doesn't start or won't open.
You can always get back to let me know how it goes or if you have other concerns. I'd be happy to lend a helping hand. Have a beautiful day.
