If you've lost an unsaved Microsoft Word  document due to a software crash, you can locate the most recent auto-save of your document by following these steps.

IMPORTANT: You can only recover unsaved work if it is the result of a CRASH. If the software determines that everything is functioning properly upon quitting, it will DELETE THE AUTO-SAVE.

1. Generally speaking, if Microsoft Word  crashes, it will prompt you to Restart The App and automatically recover any unsaved documents. If this does not occur, continue with the following steps.
2. Open a new Finder  window. Click the Go menu, and click on Go to Folder...
   
    
3. Enter the file path ~/Library/Containers/com.microsoft.Word/Data/Library/Preferences/AutoRecovery/ (you can copy and paste it from here). Make sure you don't delete or alter any files as it may affect the running of some applications or your computer as a whole.
   
    
4. In this folder you should find a file named "AutoRecovery save of <filename>", where <filename> is whatever you had named your document. If it hadn't been saved at all prior to the software crashing it will be DocumentX (X being the sequential number Word automatically assigns to unsaved documents). It will most likely be Document1, as in the example below.
   
    
5. As this is not a regular Word document you will need to specify which application will open the file. You can do this by Right-Clicking (or Control-Clicking) the file, and selecting Open With > Microsoft Word.
   
   
    
6. You will then be able to save your recovered document to a location of your choice using File > Save As...

Of course, the best way to avoid having to go through this process is to make sure you save your work regularly!