I have not seen this mentioned in this website, but others have posted the issue on Apple’s Support site. Three times now Mail has deleted my entire Hotmail inbox when I deleted my junk mail folder. Do not do select all-delete in the Junk mail folder or it will also delete your inbox! One time I could understand it was my fault, but not 3 times! I had to spend 30 min recovering my emails from Trash and I lost many older emails.