In case you have created master page in your file with buttons and have duplicated the states on master page. Opening the file and previewing the file could be slow because of a known issue. Please delete the duplicate states that you have created in the master page and recreate them as new states.
Suppose a file has master page with few buttons in State1 and you have duplicated 5 states , you will need to delete the States from 2 to 6 and create them as new states instead of duplicating. Creating duplicate states on a Master page with buttons is adding some overhead while opening and previewing the file.
To add to this, I found that I did not have to delete the states, but merely remove the button symbols from the duplicates. Loading/saving time improved noticebly.
Is my method a workable one, or am I asking for trouble?