Disable Adobe InCopy Assignments at the Domain/Site
Make sure the red highlighted option is UNchecked if you do not need to make Adobe InCopy assignment files. The Assignment files are only used by sites that are actively using Adobe InCopy. This option, if checked, would tend to cause each placed asset to generate an Adobe InCopy Assignment file and slow down all users in the process.
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This article describes in excruciating detail the steps to go through to make sure that Adobe InCopy assignments are no longer created.