Problems compiling

I’ve tried exporting my file a few times. I’m using Ubuntu and LibreOffice. I tried exporting the file as a .doc, and it opened fine the first time but then when I made some edits, saved it, and closed the file, it wouldn’t open any more. I tried making some edits and saving it as a .dox, but that made LibreOffice freeze every time I tried opening it. Then I tried saving it as a .odt but when I tried to open it it wouldn’t open at all, and I got an error message saying that there had been a Read Error, and that there was a format error discovered in the file sub-document content.xml at 504.67(row,col). Help! I wonder if it’s partly because the file is very large (it’s about 4MB as a .doc)? But it’s not a lot of use being able to compile a file if I can’t then read it!