UserAgent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/61.0.3163.100 Safari/537.36

Steps to reproduce the problem:
1. Open bookmarks manager
2. Export bookmarks to the html file
3. confirm saving operation in save file window
4. Change something in bookmarks export it again
5. Export bookmarks to the html file
6. confirm saving operation in save file window
7. Try to import bookmarks from first file (you can't because there will be only one file)

What is the expected behavior?
show a confirmation window (like "existing file exist, do you want to replace it?")

What went wrong?
I wanted to sync part of bookmarks from Chrome Profile 1 to Chrome Profile 2. I exported bookmarks from Chrome Profile 1. After that, I exported bookmarks from Chrome Profile 2. I saw no confirmation window and names for files were the same, so the second file replaced the first file without any notice. Unfortunately, I removed bookmarks form the Chrome Profile 1 already, so I lost them completely. It was a bad experience. 

Did this work before? N/A 

Chrome version: 61.0.3163.100  Channel: stable
OS Version: 10.0
Flash Version: