Teammate sent me a packaged workbook via outlook. I must have opened it instead of save as. Made a lot of changes. Thought I was sending back but I think the version Outlook was suggesting was not the new version and I inadvertently sent back the original version. Before I realized that, I went to the email i sent to open it, which required me to extract / unzip, noticed it was the original version not mine. I am thinking that since I inadvertently sent back the original, it unzipped over my newer version. I have looked in Autosave folder, used a directory tool on my machine, everything I can think of. Lesson learned to Save As at a minimum but nay ideas to save me from hours of re-work? Would greatly appreciate it.