Thanks for the informative links; I’ll definitely save them for future reference.
To solve the error message however, I think I need to find where the missing global scenery file is and move it to the correct folder.
The log file does note the error but does not say what specific file.
My mention of a directory tree, file paths and file type (*.xyz) unique to x-plane 10.5, might be helpful for some of us less gifted in computer-ease to repair errant file issues.