Keil MDK Licensing Error: Serial does not match product requested

Hi everyone,

I'm running into a licensing issue when building my project using Keil MDK Professional 5.42 with ARM Compiler 5.06 update 6 (build 750).

I've already activated my license using a valid activation code and confirmed that my µVision shows MDK-Professional. However, I keep getting the following error when I try to compile:

What I’ve already tried:

• Restarted µVision after activation.

• Verified that TOOLS.INI has:

  TOOL_VARIANT=mdk_pro
FLEX_USE=0

  
  
  
  
  System Info

• Keil MDK Version: 5.42

• License Type: Activation Code

• Compiler: ARM Compiler 5.06 update 6 (build 750)

• Target MCU: ARM7TDMI (LPC2138)

• OS: Windows 11

Appreciate any guidance or help — this is blocking my build. Thanks in advance!