I run SDL Trados Studio 2017 SR1 - 14.1.10014.38031. Each time I try to create a return package, I first get a warning message saying "The process cannot access the files because they are being used by another process" followed by an error message "Object reference not set to an instance of an object". After confirming the error message, it reappears when trying to cancel the Create return package wizard, unless you go back to the first screen where you select files, in which case the wizard can be cancelled without the error message. Seems like this occurs with any projects I receive from different clients, and the issue did not appear until the installation of the latest cumulative update. I have explored the knowledgebase in the past few days, but did not find the exact solution or anything. So I wonder if anyone had experienced the same issue and is there a solution to it?