Hi!
It could be that the reference to gpdsc file within the uVision project is not up to date and wrong. Can you please open the 'Project.uvprojx' file with a text editor and verify whether the gpdsc description is correct? You'll find the adequate section at the end of the XML file, like this:
<RTE>
<gpdscs>
<gpdsc name="..\..\GeneratedCode\ewfiles.gpdsc">
<targetInfos>
<targetInfo name="STM32429I-DISCOVERY"/>
</targetInfos>
</gpdsc>
</gpdscs>
<apis/>
<components/>
<files/>
</RTE>
Hope this helps!
Best regards,
Manuel