If you haven't rebooted Windows since you installed the latest software update, please do so now and then try Quicken again.
Still not working?
Let's try some "Troubleshooting 101" to ensure the Quicken software is installed and updated properly and that your data file is in good working order. Please perform all the steps in this document:Troubleshooting 101 - Fixing Software Installation and Data File Problems
Check if Windows Defender feature Ransomware protection is enabled. If so, configure it to add Quicken as an "allowed app" without turning off Ransomware protection:https://community.quicken.com/discussion/7857675/faq-windows-defender-controlled-folder-access
https://www.quicken.com/support#contact-support