Cannot figure out what happened. It worked Feb. 16 but does not work now. I cannot see where I was charged for the software. I am under the impression I purchased it and it was not the free sample.
I have checked the Changelog of the software, and it's specified that the software is working just fine on El Capitan. I recommend re-downloading the software on your Mac using the link posted below.
You can check the following release notes to see compatibility with El Capitan and other bugfixes/features: https://www.hamrick.com/vuescan/vuescan.htm#changes
Download page: https://www.hamrick.com/download.html