This is article is for cases like the loading wheel on Quick Preview mode, when the file opening takes more than a minute.

If you experience something like that or your Mac is slow or unresponsive, do following actions:

1) Open Finder and hit Shift+Cmd+C combination

2) Enter ~/Library/Caches in an appeared window and hit Enter

3) Select all the files and remove them by hitting Cmd+Backspace

4) Delete all the removed files from the Bin