I plan to reinstall my system or change computer and want to transfer my current IDM settings and download list. How can I do it?

You need to do the following:

1. Open "Options→Save To" dialog ("Options→Downloads" for old versions) and look what folder is set in "Temporary directory" field (arrow 1 on the image). Save this folder somewhere in order to use it later. Do the same for each category download folder to save your completed downloads. To see path for each category folder select them in "Category" listbox (arrow 2 on the image).

Please note that by default "AppData" folder ("Application Data" for Windows XP) is hidden. Please read here how to see hidden folders in Windows Explorer.

Folders you need to save to transfer IDM downloads

3. After your system reinstall or on a new computer import registry key that you have saved. Then copy IDM temporary folder and all category download folders under same paths that they had on initial system.

Then run IDM. If you done everything correct, IDM will use your old settings. You should see a list of your downloads and be able to resume unfinished downloads.