In order to use the full version, you need to download the correct version and log in to the application with the correct license email to activate the software. Kindly follow the steps below to try again and see if it works.
Please make sure that you have downloaded the correct version from the following link:
X86：https://download.wondershare.com/uniconverter16-mac_16.0.0_full14207.zipARM：https://download.wondershare.com/uniconverter16-mac_arm_16.0.0_full14207.zip
After the successful installation, please open UniConverter on your computer, and click the avatar icon in the upper right corner.
log in with your license email and the password you set to activate the application then you will have the full version of it.