Steps to fix when Quickbooks won't open in windows 10
Check your internet connection. Poor or no internet connection can be the reason.
Restart your computer. This can help reset the system and help you open QuickBooks.
Check if you have the most recent version of QuickBooks. If not, update your version.
Check if your antivirus is blocking QuickBooks from running. Temporarily disable your antivirus and try to open QuickBooks.
Make certain that your Windows user has administrative rights.
Check your firewall settings. Your firewall could be blocking QuickBooks from running.