it is a one-page document. I just read it two days ago. Now can’t open. Very Important Document.
Did you move or rename the document after you closed it? Look for it using a file manager or OS search function
Has your OS been updated in the last two days? It might be a new security feature, see my answer to question 267726
I just read it two days ago
This makes my gut feel, that you downloaded the file using your browser and instructed your browser to open the file using Writer application instead of saving it to your disk. If that’s, what you did, the file most probably is really deleted because it “lived” in the browser’s cache as long as the browser application was active. Closing the browser deleted the cached file. Just hover your mouse to the thumbnail ins LibreOffice start center and you’ll get the location where it was when you opened the file for the last time.
PS: What should tag *base-macro* tell us? I can neither see how your problem is related to database module *Base* nor how it is related to *macro* programming.