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C51: Warning C500: Serial Number Expired

Information in this article applies to:

  • C51 All Versions


I just downloaded and installed an update and I now receive the following message when I compile:

Warning C500: Serial Number Expired

What does this mean?


Your License ID Code (LIC) contains your serial number and the date that your product support agreement expires. If you download and install a version of the C51 tools released after your expiration date, you will receive this message. At this point, the new C51 product will either run as an evaluation version or not work at all, depending on the type of license you have.

Keil Software offers technical support and product updates for one year after your product purchase. When your serial number expires, to use the new C51 version, you will need to renew your technical support contract.

To renew your support contract, you may contact the distributor you purchased your software from or the Keil Sales Department at sales department. Be sure to include your expired serial number in your correspondence, as this makes it easier to locate your information in our database.

Last Reviewed: Wednesday, August 7, 2013

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