QuickBook Error 1603 is a common error, while you open QuickBooks Desktop after install or updating.
Warning message show in your system:
Update installer face internal error
Unable to apply the patch
Error during installation
Causes:
▶ Missing windows installer components
▶ Issue in Microsoft.Net framework
▶ Windows Error
▶ Damaged QuickBooks Installation files
▶ Download QuickBooks Tool Hub
▶ Update your window
▶ Repair MSXML
▶ Uninstall QB Desktop
▶ Update QuickBooks Desktop to the latest version
Any help and support dial 1800-986-6931 or live chat 24/7 resolve your issue instant.
Source: https://www.onlinechat247.org/quickbooks-error-1603/