Rebuilding Search Index Crash

I can no longer access my book project - every time I open it, it cycles through rebuilding search indexes until it hits Recovered File 1, at which point it crashes. I’ve tried deleting the files from yesterday (the last time it worked), deleting research pdfs, downgrading to the 3.1.2 - nothing works. Any help with this would be most appreciated!

Appears to be solved - I kept deleting old files until the project finally opened.