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LICENSE: Licensing Error R201

Information in this knowledgebase article applies to:


During Compilation, I see the licensing error R201, i.e.:


What are possible causes, and how can I fix this error?


License error R201 appears if the current CID (Computer ID) does not match the CID encoded in the LIC (License ID Code) found in the file: C:\Keil\TOOLS.ini.

Several circumstances lead to such a mismatch:

  • Wrong LIC
    If you have copied the Keil installation folder, you may also have replicated the TOOLS.ini. Such a TOOLS.ini can then point to old LIC, or a LIC from some other computer. If the product locates such an outdated TOOLS.ini, this mismatch is created. Solution: Search your computer for multiple appearances of TOOLS.ini, identify the outdated versions and remove them.
  • Hardware changes
    If parts of the computer were changed, or if the hard disk was significantly modified (like formatted or OS upgrade) then relevant parts of the CID did change, causing the mismatch. SolutionUninstall the LIC and then request a new LIC.
  • Multi-Processor system
    If the computer has multiple processors (not cores in 1 processor), the CID generation is not constant, causing the mismatch. Solution: µVision: Dual Processor PCs and µVision

Contact the Keil Support if the problem persists.



Last Reviewed: Wednesday, October 21, 2020

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