Today, on my professional computer, I wanted to open a personal document (PDF) directly from Dropbox website. However, it was impossible for Dropbox to show a preview of this PDF file (This file can’t be previewed). Actually, I couldn't preview any of the files stored on my Dropbox, and downloading them didn't help either.

My Dropbox is synchronized with a local folder on my Mac, on which FileVault is activated.

I have another folder on my Mac which is synchronized with a webserver, using Nextcloud's app (similar to Owncloud). When using the web interface of Nextcloud, I couldn't open the files either.

Is it possible that, with FileVault activated, an encrypted version of my files are stored on Dropbox and Nextcloud server?

If yes, is there a way to circumvent this issue?

I didn't have this problem in the past, but since I activated FileVault some weeks ago, I thought it could be the cause.


No, there's no possibility of FileVault suddenly "activating" and encrypted the contents of just one file. This is not at all how FileVault works.

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  • You mean that FileVault puts a fence around my house, but doesn't put a lock on every object of my house? – peter Mar 28 '18 at 7:03
  • I do not like analogies when dealing with cryptography, as you tend to get things wrong. FileVault does not encrypt each file individually, but instead encrypts the whole filesystem as a block device. This means that each file is encrypted, but not individually. So you cannot have one file encrypted and another file not encrypted on the same file system with FileVault. Nor is it so that the user is exposed to the encrypted version of any file, so it cannot be the reason for PDF files that cannot be viewed. – jksoegaard Mar 28 '18 at 14:40

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