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Product Assistance

Arm Keil Technical Support provides online and telephone assistance to licensed customers with a valid support and maintenance contract. This includes installing, configuring and operating the Keil C51, C251, C166, MDK-ARM and DS-MDK software (referred to collectively as the Arm Keil tools) and associated Arm Keil hardware products.

We also provide free licensing assistance to all licensed customers regardless of product expiration or release date.

Questions about the use of third-party IDEs or plug-ins to the Arm Keil tools should be directed to the third-party supplier where they will be addressed more efficiently.

How To Contact Keil Technical Support

For support communication ARM uses a web-based support system called This system files, tracks and answers all support cases. Accessing and using the system just requires a few steps:

(Click each section to expand it and view the details)

1. Register on
  1. Press the button below and fill out the form to create an account.
    Register a new account
  2. Please have your IT department whitelist these email addresses:
  3. Open the email received from Click the link in the email to activate the account. Activation grants you immediate access to
  4. You may already be registered.

    An account may already exist for your email address if you previously submitted a case via email.

    If this could be the case, press the button below, enter your email address and reset the password to gain access to your existing account.

    Reset the password (existing account)
(Optional) Update your contact information for better service

We try to route your case to support analyst closest to your times zone. Make sure your contact information is correct, especially the country.

  1. On the top right of the screen, click the person icon and select my profile. open the my profile page
    … or even faster click the button below to go the profile page:
    Edit your profile

  2. Update the information - especially the country - and click the Save button. Update the information and press save
  3. On the right of the screen under Services, click Support - this opens the My cases page.
3. Go to My Cases

After a successful login, your personal welcome page appears. If not, go to the My cases page. Click on Open a new Case.

Open a new case

4. Fill out the New Case form

Fill out the four sections in the New case wizard to create a case for Keil Technical support.

  • Click the Continue button on each screen to advanced to the next screen.
  • Click the black circle with a back arrow to go back to the previous screen.

Fill out the first two screens exactly as shown - even for hardware, download, or licensing issues - otherwise the case might be misrouted to another division within Arm.

  1. On the first screen of the Open a new case wizard, choose:

    What would you like to open a case about?

      I have an issue downloading my product
      I have a question about licensing my tools
    ⦿  I have a technical issue with my product
      I don't have a product

  2. On the second screen of the Open a new case wizard, choose

    What would you like to open a case about?

      I have an issue with the product documentation
      I have a hardware tool, for example a development board, that has a fault
      I have an issue with my Physical IP product
    ⦿  I have a different technical issue with my product

  3. On the third screen of the Open a new case wizard:

    • Select Software Tools from the first drop-down list
    • Then select the Keil product, e.g., Keil MDK
    • To find the LIC: open μVision, and from the Help pull-down menu select About μVision - the dialog opens. Click the Copy Info button. Paste the result into a text editor to locate the LIC. Click here for an example.

    In create new case, choose the Keil product

  4. On the forth screen of the Open a new case wizard, fill out the form and click Create case.

5. Get your answer

Customer Code

Rather than provide programming assistance to debug code, our approach is to show you how to use the Arm Keil tools to help you identify problems in your code. If you think you’ve identified a product problem, we may troubleshoot application code up to the point of determining if the Arm Keil tools are performing as documented.

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