Captivate 2017 files (cptx) displaying as Adobe Acrobat Document (pdf) in Windows Explorer

Thank you Paul and Lilybiri for your suggestions,

I ended up uninstalling Captivate 2017 and reinstalling. This allowed me to go to the Properties and then I could see an option to select Captivate as the default application to open cptx files. Problem solved

The procedure varies slightly from one Windows version to the next but for Windows 10 the following steps should get you straightened away.

1. Right click on the CPTX file and Select Open With...
2. Check off "Always use this app to open CPTX files"
3. Check off Click on More Apps if necessary to find Adobe Captivate 2017
4. Click on Adobe Captivate to open your file and also reassign Adobe Captivate as the default application for opening CPTX files.

I never open a file directly by double-clicking on it, but always open the application first. Reason is that I have several versons of CP installed, and Windows doesn't always recognize the correct version. This is an old 'habit' that I have taken on since many years, because it also happens with other applications. I cannot give you another solution, suppose you have already tried to restore the link between the extension cptx and the applicaiton Captivate?