Keil Logo

µVISION: Error: Encountered an improper argument

Information in this knowledgebase article applies to:

  • MDK v5.x


Under some circumstances, an error dialog with the text Encountered an improper argument might show up when you exit a debug session. If this happens, µVision needs to be terminated with the Windows Task Manager. In most cases, customers with Asian Windows versions are affected by this issue when Asian characters are used in the project path.


The µVision 5 debugger is currently not able to process DWARF debug information which contains folder or file names with UTF-8 characters.


Use only ASCII characters in the folder and file names of your project and all your source files and libraries.


Last Reviewed: Thursday, January 7, 2021

Did this article provide the answer you needed?
Not Sure
  Arm logo
Important information

This site uses cookies to store information on your computer. By continuing to use our site, you consent to our cookies.

Change Settings

Privacy Policy Update

Arm’s Privacy Policy has been updated. By continuing to use our site, you consent to Arm’s Privacy Policy. Please review our Privacy Policy to learn more about our collection, use and transfers
of your data.