I have the same problem, so you're not alone.
There are some solutions and workarounds in this thread:
You can also return to InDesign CC 2014 until the bugs are fixed if the solutions/workarounds don't work:
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I just found that thread. Killing the library process and deleting the folder from Applications:Utilities:Adobe Creative Cloud has cured the problem. for me (so far).
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I did this , launched the app again and it seems to have solved the problem. Thanks.