All my words disappeared. need help!!!!

Yesterday while I opened Scrivener, I saw this message. “Search index was not fully loaded. Your first project search might be slow. this might be caused by nonstandard characters within documents contents. You might also try tools> save and rebuild search indexes to fix the problem.”
Tried it didn’t work. Lost all but one of my chapters. when I pressed okay it went to this message.
The project you are trying to load uses an older file format and can not be opened. Would you like to update it? A copy of the old project will be saved in the same directory."
when I open it only one chapter is saved.

I am bumping this post as this error also popped up for me, so I am following this post. I receive the same error message of, “Search Index was not fully loaded. Your first project search might be slow. This might be caused by non-standard characters within the document contents. You might also try “Tools > Save and Rebuild Search Indexes” to fix the problem.” I do what it says and it doesn’t do anything.

Yesterday it wiped out the entirety of a new project save for my files on characters, but all the writing was gone. This morning most of it is there, except for the last half, which is just black blocks in the shapes of paragraphs as opposed to actual words. Any help would be greatly appreciated!