To stop downloading a website and start downloading later where it has stopped,
follow these steps(HTTrack 3.49.2):

*** Pausing ***

1-To pause, click the "Cancel" button and then click the "OK" button in the
popup window.

2-Stay tuned for the program to store all the files it has in its cache on
your device. This may take time.

3-After the program has saved all files, click the "Finish" button.

4-You can now exit the application.


*** Resume the download***

1- Run HTTrack Website Copier

2-In the start window, click the "Next" button.

3-In the "Project name" drop-down box, select the name of the project you want
to work on.

4-click the "Next" button.

5-In the "Action" drop-down box, select the "*Continue interrupted download".

6-click the "Next" button.

7-click the "Finish" button to Start downloading from where it paused.