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LICENSE: Flex License Error -7,10015 and C9555E After Tools Update

Information in this knowledgebase article applies to:

  • MDK versions 5.12 and later


After updating to MDK version 5.12, compiling a project fails. The FlexNet license server reports the following licensing error code:

Error: C9555E: License checkout for feature mdk_pro_compiler5 with
version 5.0201409 has been denied by Flex back-end. Error code: -7
No socket connection to license server manager.

(Alternative licensing error codes could be A9555E, L9555E, or Q9555E)

The FlexNet license server could also report the Flex error code:

FlexNet Licensing error:-7,10015

No other changes were made to the computer, application or IDE.


MDK version 5.12 and later use new licensing capabilities - which requires updating the licensing server to a newer version of the FlexNet software licensing utilities. This was already announced in the ReleaseNotes of MDK 5.12. Using older versions of FlexNet (formerly called FlexNet) causes licensing errors.


MDK version 5.12 and later require FlexNet version Download and install the latest FlexNet binaries; follow the steps listed in FlexNet Publisher Setup (Server) guide.

Note: FlexNet V11.12.1.0 supports:

Resolve this issue by:

  • Check the FlexNet licensing server version
  • Verify the license server is running
  • Update the FlexNet license server


There are 3 main ways to verify server information:

  1. Ask your license administrator
  2. Use the lmutil command line tool found at C:\Keil_v5\UV4\FlexNet\lmutil.exe . The invocation syntax is:
    lmutil lmstat -c Port@LicenseServer
  3. Use the lmtools.exe GUI tool (Windows only)
    You can find this tool in the MDK directory ..\Keil_v5\UV4\FlexNet. Start it with a double click and select the items marked in red.

    Then select the tab Server Status and press the button Perform Status Enquiry. You will see the same output as with the commandline tool lmutil lmstat above.


If the FlexNet version is older than, perform these steps for a smooth update:



Last Reviewed: Wednesday, July 10, 2019

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