Help - Why does data file get 'lost' between conversion to and from Word

I use a system which requires a conversion to and from MS Word/ Libre. I have lost at least 1 file with 11 documents which don’t seem to be recoverable - this is not the first time and it makes, me and my manager cross as we have to attempt a recovery, which takes a long time and isn’t very successful

Over many years using OpenOffice, I have never experienced any loss except for formatting. You should be more specific about the problem that you encounter.