Complete the items on the checklist below to troubleshoot this issue:
Use only the Username/Password/License Key generated for you and sent to the email address you provided while registering/purchasing a license. For example:
Copy and paste your Username and Password, or License Key (depending on product version) into the activation screen and be sure not to select an extra blank space
If you cannot copy and paste, type your Username and Password, or License Key, EXACTLY as they are written:
If your Username and Password, or License Key still do not work:
Clear the update cache in your ESET Windows home product. Click to view instructions.