I was working with a customer who was upgrading all of their PCs from Windows 7 to Windows 10. Many of the existing programs were old, outdated, and incompatible with Windows 10.
 
One particular issue we had was installing their Digital Persona fingerprint scanner to work with the TIB website. It turns out that on HP devices that have HP Protect Tools, or any of the built in HP security software features, those must be uninstalled first before the fingerprint reader software will install.
 
I uninstalled Protect Tools, and tried to run the fingerprint scanner installer again, but received an error that HP Protect Tools was still installed. Research showed to rename certain folders in C:\programs and even to rename certain .dll files as well. Did all of that, and it still showed that Protect Tools was installed.
 
I called support for TIB since they were the ones that provided the initial troubleshooting steps, and it was their fingerprint scanner. They were unable to help beyond mentioning the .dll files to rename. I then called HP support to see if there were any particular registry keys that I might need to change to prevent the error. They said there were not any, and suggested that I would need to reinstall the OS to remove any of their preinstalled software. This was not a viable solution as I had spent hours already installing other software, and this was one of the last items remaining on our list of programs to install. I continued to research and one article suggested I would need to go to HP website and reinstall Protect Tools, and then uninstall it again.
 
I reinstalled Protect Tools and then went through the uninstall process again. This time I paid closer attention to the uninstaller. While the uninstaller is running, there are a few prompts that come up, asking for verification of uninstallation. One of those prompts is a little sneaky and turned out to be the culprit. It is a yes/no prompt and asks if you wish to proceed with uninstallation. It provides information about the uninstall, but if you keep reading, it says "Press Yes to save current settings and preserve data for future use, Press No to completely uninstall."  Those aren't the exact words, but something similar. I clicked No and after the Protect Tools uninstaller finished, the Digital Persona software installed without issues.