I've not had a real problem opening projects going back to ver 8.5. The files always open. My problem is with the synths I've used on those projects. A typical example would be the program telling me that Rapture is not available and is required for tracks 3 & 5. Rapture IS available and always has been. I'm using all the default file locations, as I have ever since I got involved with Sonar.
 
That problem is annoying, but not fatal. I've always wondered why Sonar doesn't seem to find the bundled soft synths when I open old projects. 

It s possible the Rapture used in the legacy projects is DirectX? If so, the host needs the appropriate DirectX plug-in to load in the project. There is no facility to replace a DirectX plug-in with the appropriate VST version.

That's a good question scook. I'll have to look into that. I assumed that the full versions of Dim Pro and Rapture would always be supported. They still work fine and I didn't realise that Direct X could be a compatibility issue.
 
Time for me to do some sleuthing.

Noel Borthwick [Cakewalk]
 
Thats an incorrect speculation. You can load and save a project as many times you want and there is no bloat. If there is it would be considered a bug. There were some issues with Audiosnap a long time ago which could cause excessive markers. But with plugins there is no such issue of "bloat".

The "bloat" I'm referring to is not speculation. I experience it. The reason for the bloat IS pure speculation.
 
As I compose in a project, I generally write MIDI in staff view. I try many VSTi instruments before settling on the ones I'll ultimately keep. I'll write a few tracks, load instruments, delete instruments, load new instruments, freeze then bounce to audio, clone the track, then delete them all except the original MIDI and start again. Many times throughout this process I "Save As" to keep different versions. When I am ultimately "finished" with writing in the project, I bounce everything to audio, delete all MIDI tracks and VSTi instruments that were loaded and start "mixing", again "Saving As". Each iteration of the project shows a larger file size even though I have gone from 40 tracks down to 10, and from dozens of VSTis down to none and 10-20 MIDI tracks down to none.
 
Am I the only one experiencing this?

Sorry I didn't intend to marginalize what you are observing - sorry if it came off that way. If all you have in the project are instruments and MIDI, I'd be interested in see some of the iterations of the project that keep increasing in size - esp if you can demonstrate that simply re-saving the same project with a given set of instruments increases the size. SONAR should be saving exactly the same data no matter how many times you save it - timestamps etc may change but the size should not assuming no new data was added. 
 
FWIW I have a few projects that have gone through months of iterations some that came from Version 8 or earlier. None of them exhibit bloat or instability so I can't say I've ever experienced this personally. I don't use many virtual instruments though. Maybe a couple per project at most. Any of the symptoms you describe could very well relate to plugin bugs however so its very possible that one user might exhibit a problem that someone else doesn't, depending on the plugins in use.
 
Bottom line is investigation is required before a conclusion can be reached in such cases because there are a lot of variables. We take project persistence issues very seriously, so if a demonstrable problem is found in SONAR that causes problems it will get fixed quickly if identified as a SONAR bug. Mark any logged issues in this area as "SONAR persistence" so that it can be highlighted more easily.

ampfixer
I've not had a real problem opening projects going back to ver 8.5. The files always open. My problem is with the synths I've used on those projects. A typical example would be the program telling me that Rapture is not available and is required for tracks 3 & 5. Rapture IS available and always has been. I'm using all the default file locations, as I have ever since I got involved with Sonar.
 
That problem is annoying, but not fatal. I've always wondered why Sonar doesn't seem to find the bundled soft synths when I open old projects. 

Scook mentioned the DX issue. Besides that, around X2 we addressed a common problem with plugins identification caused by short file names that could change. Older projects don't use the new identification system so could be prone to that issue. However if you re-save the project in a new version of SONAR the issue should not recur.

Noel Borthwick [Cakewalk]
...Bitbridge is a sandbox albeit only for 32 bit plugins. Jbridge allows sandboxing even 64 bitplugins. The downside to sandboxing is obviously performance (and potentially other bugs). So there is no perfect solution today.

Thank you for the insights!

Noel,
The issue I tried to describe is not saving the same project as it was many times.
It is when I add tracks/synths/plugs save as then delete tracks/synths/plugs and save as again.
After I delete tracks/synths/plugs and save as a new project file, the file size does not go down.
The space for the deleted items is not released. If you do this many times, the file just keeps growing.

 I use to keep previous versions of Sonar installed just in case. The program files don't use a lot of space. On one machine I had Sonar 7 all the way to X3.  I usually avoid bun files and put everything in a folder and zipped it. Interesting though is I've never had a bun file fail.  I have one from the Gigastudio 2.5 days that opens up.
 
 In general older projects are not fool proof on most DAWs except really simple ones like EnergyXT.

I'm I missing something or would not  a project that was originally midi and soft synths that was bounced to audio certainly become larger. Audio tracks are what takes up data size. 
A midi only CWP file will not be very large. 
As far as I can tell if you "save as" to a new folder location and tell it to "copy audio"  it will leave old audio files behind in the old location.
If you just "save as" in the same folder, the old unused auido is still there.