Hi,
I wasn't able to find the solution to this error on the forum but while trying random things I was able to resolve it. Just hoping this might help others who may experience it.
While running version 0.3.108 on my Mac I got into a state where it was unable to save the current project. It would append the name that I specified to the end of the last file that I was successfully able to write to. Closing the application, removing the application, deleting the .json config file did not resolve this.
What resolved it was changing the save path to my documents folder.
I have enjoyed using this program, keep up the good work!