After Windows 11 Update, some users may encounter issues when starting QuickBooks. Common problems include compatibility issues, missing or corrupted files, and conflicts with other software. To troubleshoot, first ensure that QuickBooks and Windows 11 are fully updated. Next, run the QuickBooks Install Diagnostic Tool to fix any installation errors. If issues persist, try running QuickBooks in compatibility mode for Windows 10. Additionally, check that all necessary Windows components, like .NET Framework, are enabled. If QuickBooks still won't start, consider performing a clean install of the software or consulting with QuickBooks support for further assistance.