: In Acrobat, go to Preferences > Security (Enhanced) and uncheck "Enable Protected Mode at startup" . This is the most common fix for serial numbers not being remembered.
If you lost your serial, email Quite Software with your purchase receipt – they will resend it. quite imposing plus 53 serial number fixed
The most reliable way to handle a "Serial Number Fixed" error in Quite Imposing Plus 5.3 is to perform a clean re-installation of the plugin and ensure your Private ID matches the Registered Name exactly. If you have lost your codes, the Quite Software support team is famously helpful at retrieving licenses for verified purchasers. : In Acrobat, go to Preferences > Security
If your document lacks numbering, use this tool to add "fixed" text or automatic page counts before printing. : In Acrobat