If you purchased ESET Mobile Security from Micro Center, you need to download the Micro Center version of ESET Mobile Security to successfully activate your product.
Tap Settings (in some cases, Menu → Settings) → Applications (or Manage Applications), and then tap the check box next to Unknown Sources. Tap OK to continue.
On your Android device, visit the following link to download the ESET Mobile Security for Android installer:
When the download is finished, open the .apk file on your Android device using a file browsing utility and follow the instructions on-screen to install ESET Mobile Security for Android.
Tap the Menu icon .
Tap Enter a License Key.
Type the License Key (hyphens are added automatically) from the Installation and Activation card included with your Micro Center purchase into the field and tap Activate.
When verification of your license is completed, Activation successful will be displayed. Tap Finish to close the window.