Hi everyone,
did this situation happen to any of you where the dictionaries in the Apple Dictionary app all disappeared? I opened the app after upgrading to Sierra and found out that Apple dictionary and Oxford dictionary were not installed anymore. A German thesaurus which I think I installed myself remains available. I have a backup of all the dictionaries, which I copied to Sytem Library but they are not recognised by Dictionary app.
This happened to me and I just figured out what the issue was in my case.
I upgraded my Macbook Pro to Mac OS Sierra and all of the dictionaries went missing and I couldn't download them again. Turns out that my work's web filter was blocking access to the URL in which the Dictionary.app accesses to see if you have the dictionary and then download it. I looked in the .plist file of a working Mac at /System/Library/Assets and saw "http://appldnld.apple.com/osxassets/058-55450-2016008023-8A4D782E-661F-11E6-B483-D75733D2D062"
When trying to access this via a web browser, I was being blocked by the webfilter. After whitelisting. everything worked fine and I was able to download the dictionaries again.
