Adobe has addressed the bug and fixed it in v. 11.1.1 of the software. So update!
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I haven't experience this bug, thank you very much, but be warned!
Click these links below and read on and act appropriately in order not to loose them precious files. Hopefully Adobe will discover the problem and issue a fix soon.
This news come at a time when I have been thinking of storing all apps caches onto a separate SSD to speed up things. Well, good thing I haven't implemented that plan yet.
Another reminder to always have a backup up-to-date.
Be wary of the Media Cache!
http://www.newsshooter.com/2017/05/10/adobe-premiere-pro-version-2017-1-users-reporting-media-files-completely-disappearing/
https://forums.adobe.com/message/9503050#9503050
