Build problems with Eclipse

During the Vaadin 14+ development I face sometimes following problem caused by the change code & stop/start tomcat cycle and the case auto restart of the running tomcat after saving modified code.

OS: Window 10

The vaadin build process triggered by loading the site, the npm part, is sometimes out of order - all the helper dirs and js files like the target dir will be created in

system32 - fails missing due rights
or on the Desktop, this works

but due the fact that all this these possibilities are wrong paths, the start of the app inside the browser fails. In all these cases the auto rebuild, triggered by code changes, was done by the eclipse build system. In this case, I must perform a explicit maven rebuild to correct this problem.

This a random, but annoying problem.