If you still can't solve your trouble and don't know how to repair ppt. I would suggest you to use online-service, it was created for any device, only upload your problem file there and after see how it handle your issue. It was found from Google.
I use PowerPoint, to postpone presentation at conferences and to write a PC on Windows. Most of the work I did in the PowerPoint version of 2010. But recently I had to switch to macOS, and all my work too. Now I notice that some of my files don't open in the version for mac. How can I transfer an old job to a new device?
How to open ppt, created in the program of the old version?