older pages documents not opening after upgrading to yosemite

Upgraded to yosemite, thus also to latest pages version. Now when I want to open documents made prior to upgrading I they won't open and I keep getting the same redundant message "You need a newer version of Pages to open this document. You can download the latest version of Pages from the Mac App Store." Even preview won't open them, although I get a shadow image of the document. Strangely, time machine won't let me access anything backed up prior to the yosemite upgrade. iMac (27-inch, Mid 2011), 3.4 GHz Intel Core i7

The problem is that you have two versions of Pages on your Mac and the older version is still the default. You can find your older version of iWork apps in a separate folder under applications. You need to set the new version of Pages as the default. After that the error will no longer appear.

Nope, had uninstalled al older versions of iWork/Pages. Problem unchanged.

Not according to the error you're receiving. Something is wrong because Pages is telling you that you're trying to open those documents with the wrong version. Double check that you have actually removed all of the old version of Pages. The version of Pages that you're using should be 5.5 which is the latest from Apple.

Well, I did check, throughout the entire computer, even on the separate partition that's running under snow-leopard so that I can still access a huge volume of old appleworks (aka Claris works)-files essential to my business. Older versions of Pages/iWorks were uninstalled using Cleanmymac. Two days ago I bought a brand new macbook pro retina 15' (2.5 GHz Intel Core i7, 16 GB 1600 MHz DDR3), definitely with only one version of Pages, transferred the Pages files from the iMac with a USB stick, problem still unchanged. I run a medical practice and have an enormous amount of patient files created with Pages. Although - fortunately - most of them have been printed on paper, it's a huge time-saver, for instance when I have to write a treatment summary or a report to a health insurance provider, if I can copy text blocks from previous documents. The consequence of all this is that I have decided to avoid Apple's office software altogether and have switched to Libreoffice, which to my unbounded delight contains a nifty integrated filing program, just like there used to be in the old apple works.

That is bad antuttle, vital info like that. Hope you get it sorted soon!

Sometimes upgrades just don't do what they should first time which Is why I'll wait for Rev 1 or 2 before going to Yosemite. Hopefully by then they will have ironed out most of the problems!