
Internet Download Manager breaks a file into multiple parts when you start a download, these parts will be stored in this temporary directory: C:\Users\<username>\AppData\Roaming\IDM\DwnlData\<username>. Once the download is complete, IDM combines these parts into a single file and moves it into the directory set by the user.
It’s better for you to move IDM temporary directory to a location on your hard drive other than C or Operating system drive. This ensures you don’t lose valuable disk space and helps IDM in the faster assembling of files.
READ: Internet Download Manager update fixes IDM Integration Module Chrome Extension Disabling Issue
Deleting files in Internet Download Manager’s temporary directory
1. Open Run dialog and paste the below path and double click on username folder
%appdata%/IDM/DwnlData
2. Click on your username
3. Select and delete all the incomplete downloads in it without any doubts. They’re indeed safe to be removed.

Changing temp directory
1. Click on the IDM icon in the system tray to open its main window
2. Click on Downloads, select Options, click on ‘Save to‘, under the Temporary directory, browse and specify the directory other than the default.