Ever opened an attachment in Outlook, made changes, and then did a save instead of save as? Suck’s I know. Microsoft seems to delight it making it all but impossible to find your file. Windows search will be of absolute no help here.
So here is what you do.
First find the location of you Outlook temp directory. You can get this info from the registry
You can try navigating to this location in Windows explorer but for me it lead to a dead end, I could no see the folder it specified even though I had selected show hidden files and de-selected Hide essential operating system files. However you can access this from command prompt. Open command prompt, navigate to the folder (you can use the tab key to save time by auto populating fields) and then use the copy command to copy this file somewhere else on your computer.
Bang, Bob’s your uncle. No the only thing left to do is email Microsoft and ask them why they hate you so much.