Cannot save changes to my files using Robohelp Classic 2019

Hello. I am trying to save changes in Robohelp Classic 2019 (14.0.10.010), but I am getting an error. My project was created using Robohelp 2017.

When I first tried to open my project in Robohelp Classic 2019, I got the following error when opening the project file:

"Open project was cancelled or the application was unable to load database" for my .cpd file.

 

I deleted my .cpd file and was able to open the project, but now I cannot save changes to any of the files. I get this error when saving:

The file 'C:\docs\src\welcome.htm' could not be saved to the current destination. If you used the edit feature on your web browser to edit this file, you should use Save As on your browser, then edit the file on disk.

 

I have only edited these files in Robohelp 2017, so I don't understand the message.

 

I was wondering if I get the save error because I deleted the .cpd file? But if I don't delete it, I can't open the project.

 

I did search the forum but was not able to find anything that solved this problem. Any help appreciated!