Problem
Error 1720, 1721, or 1723 appears while installing Camtasia.
Solution
This error occurs when the installer file is incomplete or corrupt. Download the installation file from the following link: Camtasia Download
Depending on your system, there may be some other items to consider:
Reason 1: Administrator Login
You may not have Administrator Rights to install software on your computer. Login as an Administrator and then try the install again.
Reason 2: User Account Control (UAC) Blocking Windows Installer
On Windows Vista / 7, the User Account Control (UAC) could be blocking access to the Windows Installer. Disable UAC and then try to install again.
To disable the UAC, click Start Menu > Control Panel > User Accounts > User Accounts > Change User Account Control Settings. Reduce the slider position to Never Notify.