Keynote files will not open.

Keynote 6.5 should open all previous version files (except 1 and 2)

Try resetting Keynote; perform all the steps in the order listed:

1. remove Keynote version 6.5, you must use an application removal tool for this procedure to work: Appcleaner is free, I use Appzapper
2. empty the trash
3. shut Down the Mac (Apple menu > Shut Down)
4. wait 10 seconds, then press the power button
5. Immediately after you hear the startup tone, hold down the Shift key,
   release the Shift key when you see the grey Apple screen
   start up will take a few minutes longer than usual as the Mac is performing a software repair
6. restart the Mac normally, (don’t hold down any keys during startup)
7. install Keynote from the Mac App Store

RDS407,

Have you resolved this issue? I spent two weeks creating a Keynote presentation for a class, and when I attempted to open it later, it gave me the same error message -- "You need a newer version of Keynote to open this file." So frustrating! I am also using 6.5.2. I've zapped and reinstalled the application (according to Gary's instructions), re-installed Yosemite, dug up older versions through archive utility and changed file extensions from .zip to .key, ran disk repair utilities, tried to back door it by converting it to Powerpoint and back to Keynote....just about everything I can think of to do, and it STILL doesn't work.

I'm just about to lose my patience with this. Do you have ANY suggestions whatsoever???? HELP!!!!

Clean install Mac OS:

Backup all user data

start up from the recovery partition (start the Mac then press command R)

partition the drive to erase all data

re-istall Mac OS

re-install applications