I receive the error message "Serial number or Activation key already activated" or "Serial number exceeded the allowed number of activations"

KB Solution ID: SOLN872|Last Revised: September 26, 2014


  • You receive an error message when attempting to activate a serial number or activation key on the ESET website

About activating:

  • You only need to activate your activation key or serial number once. Whenever you reinstall your software, or install it on a new machine, make sure to activate using your username and password.
  • Activation issues are often due to expired licenses: Is your license expired?



If you are receiving either of the error messages shown below (see Figure 1-1) while activating on our website, you have already activated your activation key or serial number and received a Username and Password via email. You now need to activate your ESET product using your ESET-issued Username and Password by following the steps below:

Figure 1-1

  1. Locate your ESET-issued Username and Password. I can't find my Username or Password.
  2. Enter your Username and Password into your ESET product.

  3. Verify that your ESET product is updating correctly. How do I know ESET Smart Security/ESET NOD32 Antivirus is updating correctly?

If you are receiving the error message "The serial number you entered could not be found in our system" (see Figure 1-2), it is likely because you entered your serial number incorrectly.

Figure 1-2

When entering your serial number or activation key, use the following guidelines:

  • Any hyphens ("-") in the serial number must be included
  • The serial number must be entered with no spaces
  • Verify that the letter "O" was not typed instead of the number zero

If you are still unable to resolve your issue, please contact ESET Customer Care.

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