Dealing with login issues in your QuickBooks account after an update can be quite frustrating. Rest assured, I’m here to help you sort it out quickly so you can get back to managing your finances without a hitch, @Peerless12.

Firstly, please know that the error 1603 indicates a problem with the installation process or a conflict with system settings. To resolve this, I recommend installing QuickBooks Desktop again to refresh your system files. You can check out this article for further information and detailed guidance: Reinstall QuickBooks Desktop (QBDT).

If you still get the same error after reinstalling your QBDT, let's proceed and use QuickBooks Tool Hub. This tool can help us diagnose and fix common installation issues such as error 1603.

To begin the process, download and install QuickBooks Tool Hub:

1. Close QuickBooks.
2. Download the latest version of the QuickBooks Tool Hub.
3. Save the file in a location that’s easy to access, like your Downloads folder or your Windows desktop. Note: If you’ve previously installed the Tool Hub, you can check your current version by selecting the Home tab—your version will be displayed at the bottom.
4. Open the downloaded file (QuickBooksToolHub.exe).
5. Follow the on-screen instructions to install it and agree to the terms and conditions.
6. Once the installation is complete, double-click the Tool Hub icon on your desktop to launch the application.
   

Note: If you can’t locate the icon, search for QuickBooks Tool Hub in Windows and select the program.

After completing the previous steps, follow these instructions to use the QuickBooks Install Diagnostic Tool:

1. First, open the QuickBooks Tool Hub.
2. Once you're in the tool hub, click on Installation Issues.
3. From there, select the QuickBooks Install Diagnostic Tool and allow it to run—this may take up to 20 minutes.
4. After the tool has finished its work, be sure to restart your computer.

If you continue to see the error 1603, please proceed to steps 3 and 4 in this article: Fix Error 1603 when you install QuickBooks Desktop.

Moreover, you might want to check out this article to learn how to learn how to close your books: Close your books in QuickBooks Desktop.

If you have any questions or need more assistance downloading and installing QuickBooks, just let me know through the comment section below. I’m here to support you throughout the entire process, @Peerless12.