I keep having this issue when I open and close random files. All files I open and close are in PDF format. It completes the opening and/or closing of the file but still throws up this error-- "The operation cannot complete because of an unknown error. [x!fd]" It's rather irritating because I am dealing with hundreds of files throughout the day (not all at once). Files are also fairly small in size (under 1MB). Working on Mac Pro. OS High Sierra 10.13.1 Illustrator CC 20.0.1
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