"show in finder" open the file instead of opening the directory containing it
I don't know if this will solve your problem but to reset Finder you should relaunch it. To relaunch the Finder, hold down the option key and right-click on the Finder icon in the dock. A list of options will appear. The last option is Relaunch. Click that and the Finder will relaunch.

To relaunch from the terminal: open the terminal and type: 


  killall Finder


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