Keil Logo

µVISION: Error: Encountered an improper argument

Information in this knowledgebase article applies to:

  • PK51 version 9.54a which contains µVision version


When a new µVision project is created with Project - New µVision Project... and a project is already loaded, it is possible that µVision reports the error Encountered an improper argument under some circumstances for specific microcontrollers. Under Windows XP it is even possible that µVision crashes in this situation.


There was an issue in µVision version which has been identified and fixed.


Download the attached file and extract it to the folder C:\Keil_v5\UV4. If you have installed PK51 to a different folder, you need to adapt the path accordingly. The file UV4.exe is replaced with version

PK51 versions later than 9.54a will include this µVision update.



Request the files attached to this knowledgebase article.

Last Reviewed: Friday, April 20, 2018

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.