When installing an application purchased on Google Play the message "Unknown error code during application installation: "-24" pops up. The issue can be fixed by cleaning data/data и sdcard/Android/data/data from all components of the installing program. There are two ways to tackle the problem. You can do it manually or by using SD Maid - System cleaning tool.
Method 1. Clean components manually
If you confident enough and realize which files have to be removed to get things going smoothly along with Google Play, you can use ES File Manager. Just go to the folders: data/data and sdcard/Android/data/data, choose files you need, and remove them.
Method 2. Using SD Maid application
SD Maid application helps to find all unnecessary files including hidden ones remained in device’s memory after deleting applications. To use this program one has to have a root access. There is Corpse Finder function which detects all files subjected to be removed. You have to run it, then tap "Start" button and look through the menu. One can delete them all simultaneously ( by tapping "Clear all"), or select one by one.