File Sizes - Same ODT File - Different Platforms

Hi,

I just have a simple question regarding file sizes of a document I’m working on.

The document is stored in my Dropbox account so I can easily work on it from multiple devices. I started the document using my own template on my windows machine. At the end of the last editing session is was just over 5mb in size.

I then did some editing of the document (in the same version of LO) on my MacBook, once I’d saved it there ther file shrank massively to about 180kb. I opened it on my windows machine fearing the worst considering the massive diference in size but all was still there.

So I saved it again on the windows machine and it then popped back up to just under 5Mb. This is very confusing to my mind and I was wondering if there was a logical explanation for this?

Anyone have any ideas about why this happens?