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“Invalid Serial Number” error message appears when activating Trend Micro Security program

You get the following error message when trying to register or activate your Trend Micro Security:
Invalid Serial Number
"Invalid Serial Number
You must enter a valid serial number to receive protection."


"You have not provided a valid serial number. Please try again."


"You have entered an invalid serial number.
Without a valid serial number, Trend Micro Security cannot protect you. Please try again."


This issue can happen in any of the following scenario:
  • You entered the incorrect serial number
  • You downloaded a version of the Trend Micro program that is incompatible with your serial number
  • The downloaded installer of the Trend Micro program is incomplete
To resolve this issue, do the following:

STEP 1: Retype your Serial Number
The issue can happen if you used a different serial number or mistyped the serial number when activating the program. You can resolve this by changing the serial number in the program's main console. To do this, follow the steps below:
  1. Double-check the serial number of your program.
    Note: If you purchased your Trend Micro program online, you can find the serial number on the order confirmation email. If you bought the program from a retail store, look for the serial number in the sticker on the product box.

  2. Re-type your serial number.
    Enter the Serial Number


  3. Click Next
    Enter the Serial Number


STEP 2: Download the appropriate installer file
Using the serial number to activate a wrong Trend Micro program can also result in getting the error message. Serial numbers follow a different format for each program depending on how you acquired the serial number.


Check your serial number format, then download the correct installer below:
For your old Trend Micro program
Serial number starting with X
Serial number starting with P
Serial number starting with A
Serial number starting with M or X
For programs purchased from Best Buy (US)
Serial Number starting with TO
Serial Number starting with TC

Note: You can visit Best Buy's website if you need further assistance.

For programs bundled with your Dell computer
Serial Number starting with D
Serial Number starting with X
For programs purchased from QVC
Serial Number starting with A
Serial Number starting with P
For programs availed from your Internet Service Provider
Serial Number starting with TAEF
Serial Number starting with TOEF
Serial Number starting with TXEF

STEP 3: Check Installer file size before running the installer
Make sure you have downloaded the complete installer package. You may go back to STEP 2 to re-download the installer.


Note: If you still encounter the error message after performing the actions above, contact our Technical Support for assistance.

Video Tutorial

Applies To: Antivirus for Mac - 2015, Antivirus for Mac - 2016, Antivirus for Mac - 2017;Antivirus+ Security - 2015;Antivirus+ Security - 2016;Antivirus+ Security - 2017;Internet Security - 2015;Internet Security - 2016;Internet Security - 2017;Maximum Security - 2015;Maximum Security - 2016;Maximum Security - 2017;Premium Security - 2015;Premium Security - 2016;Premium Security - 2017;Titanium AntiVirus + - All;Titanium Internet Security - All;Titanium Internet Security for Mac - All;Titanium Maximum Security - All;Titanium Premium Security - All;

Last Updated: Oct. 10, 2016 4:43 AM (PST)
Solution ID: 1054753