QuickBooks Error code 1603 happens due to windows update failure. It appears when you try to open or install QuickBooks and the components which are required by QuickBooks are not available. 

Method 1: Downloading and Installing QuickBooks Tool hub.
First of all, it is recommended that you close the QuickBooks desktop.
Next step is to download the QuickBooks tool hub from the manufacturer’s website.
Now, you have to reach your download list by pressing CTRL+J.
From the list of downloads, click on QuickBookstoolhub.exe.
In order to allow this app to make changes, you need to click on YES.
Now, click on Next to begin with the installation process.
Make a click on Finish, once the process of installation is finished.

Hopefully, these troubleshooting were helpful in fixing QuickBooks Error code 1603. But, if you feel that you are stuck somewhere and you need expert assistance to fix QuickBooks error 1603,then you can call QBS Solved at +1(888) 910 1619 or you can also visit our website www.QBSsolved.com