What is the problem? Are the two highlighted faces actully part of one selected face? Delete it and use "Repair > Missing Faces" to fill the hole.
You can avoid problems like this by choosing a better import format. If you have the required license you can use one of our direct import translators from CAD systems, such as Solidworks, NX, Creo, etc... These usually produce the best geometry. If you don't have that, then 3rd party formats can be used, such as step, parasolid, acis. I would avoid iges. If one of the 3rd party formats does not produce good geometry try another format.
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