Duplicates in Library

I recently got a new computer and so installed X7 and imported my Library. However, I now find I have duplicates of every entry. (perhaps this happened with synching??)  I know how I can delete duplicates one by one but is there a way I can do all of them at once? Also, am i going to have issues with bibliographies in previous documents?

If it were me, I would do one of two things. On the desktop copy,  I would show either the last updated or added to library field and sort on that to see if the duplicates are all added more recently than the rest of the library – if so, select them and delete them – that should also delete them from the sync copy. 

Alternatively, if you still have a desktop copy on the other machine, you could start over.  Somewhere I have instructions on how to reset the library that is in the “cloud” to start over with the one on the desktop.  (Personally, I find the whole sync thing too complicated!)

sorry, i am a novice, I’m not sure how to carry out your suggestion. I no longer have the old computer.