Error Code 603 usually means you've reached your five activation limit.
If this is not the case, you can download your software directly from TurboTax. However, if this does not resolve your issue, please click the link to contact TurboTax customer support.
Follow the instructions for Starting TurboTax Desktop.
Also, here's How to Turn Off Anti-Virus Programs, which may be interfering with TurboTax activities.
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