As Mettelus stated above it appears that Aux Tracks and Patch Points are the issue with backwards compatibility.
I ran a quick test and all seems "well" after removing them.
As backup, backup, backup is the only recipe for avoiding digital disaster I am slowing making sure I have multiple
copies of everything; and removing Aux Tracks is at the top of my list of things to do with old projects.
Also, a .mid file for each project to preserve markers and tempo (midi 1; right?) seems a good idea as well.
I haven't saved a .bun file in a very long time; plenty of discussion across the forum on that over the years.
I do not yet live in fear of a Win 10 "meltdown" as I haven't migrated to '10' as yet.
But, my StudioCat, though it runs beautifully, is getting a bit "long in the tooth".
 
T
 

bobguitkillerleft

bapu
BTW, I'm not paranoid. I just know you should always have a reasonably safe/sane backup plan.
 

 
Lucky guy,must be amazing?

Yes, I seem to glide just above ground as if I'm in a hover car.

Is windows still updating Windows 7?  It would seem to make sense to have a version of Platinum on a windows 7 computer as an emergency backup as well.
 
 

DeeringAmps
As Mettelus stated above it appears that Aux Tracks and Patch Points are the issue with backwards compatibility.
I ran a quick test and all seems "well" after removing them.
As backup, backup, backup is the only recipe for avoiding digital disaster I am slowing making sure I have multiple
copies of everything; and removing Aux Tracks is at the top of my list of things to do with old projects.
Also, a .mid file for each project to preserve markers and tempo (midi 1; right?) seems a good idea as well.
I haven't saved a .bun file in a very long time; plenty of discussion across the forum on that over the years.
I do not yet live in fear of a Win 10 "meltdown" as I haven't migrated to '10' as yet.
But, my StudioCat, though it runs beautifully, is getting a bit "long in the tooth".
 
T
 

[

Because I needed a few of the old plug ins I installed 8.5. On a whim to see what a project would look like I tried to open a CWP and was told the file could not be opened because it was created on a newer version. 
So it's almost the same as trying to open on another DAW. I guess CWB files might work, I'll give that a try later. I wonder what will happen if  I tried X3? That's my back up plan. I will switch DAws before I would go back as far as 8.5. X3e would be half way there and I would use it along side Cubase. 
 
If only CWB files are backward compatable then I guess it would be wise to back up all our projects that way as we move along. Only takes a second. I save all my projects as midi as well. 

Just make an offline authorization and pull the lap top or desktop offline.
you probably wont even need to pull it offline. I say that incase you get a virus and need to reformat.
That's when you'll be screwed.