I've been cleaning up my hard drive of old projects to determine what to keep and what to delete. Sonar has had zero problems loading files from even 17 years ago, but plug-ins are a different story: no, I don't have the 32-bit version of Guitar Rig 1.0 still installed...
 
A while ago I figured out that any backup needed to include rendered, audio tracks of anything using virtual instruments and/or plug-ins, but this experience just reminded me of the importance of making sure everything exists as standard audio files in addition to whatever else is in the project, so I thought I'd pass that observation along.

Anderton
...A while ago I figured out that any backup needed to include rendered, audio tracks of anything using virtual instruments and/or plug-ins, but this experience just reminded me of the importance of making sure everything exists as standard audio files in addition to whatever else is in the project, so I thought I'd pass that observation along.

As soon as they pulled the support on Sonar, I went through the songs remaining on my next album, took Snap shots using Microsoft One Note of all Track and Console views, saved all the presets for each plug-in on every track with the song name and part, and exported all the audio tracks, plus the MIDI for Superior Drummer 3. Really simple to continue from Studio One 3 for final mixing/mastering. Yes I could have continued using Sonar to mix down the remaining songs, but I like the way Mastering is done in SO3 where if during Mastering you realize that a song needs to have the mix tweaked, you can manage that very easily in the Project page and then update. So much easier to get a handle on the Loudness levels too.
 
I am sooo glad I "panicked" and switched to Studio One 3 Pro.
 
Walt

Great advice.
 
I've learned over the years to just not consider SONAR projects backwards compatible in terms of plug-ins even if you use only bundled plug-ins. They've dumped quite a few plug-ins with newer versions which makes that infeasible -- the 32-bit DX plugins being the biggest offenders. 
 
I've also found that it isn't quite 100% true that older projects load in newer versions without issues. For example, buses (including master) do not seem to load properly in newer versions and need to be manually reconfigured. It's true that projects seem to load the raw audio and MIDI track data properly but beyond that there is a lot of manual work to recreate. 
 
I've found the Replace Synth feature of SONAR to be a godsend with updating old projects with obsolete synths to use working VSTs. 

Anderton
I've been cleaning up my hard drive of old projects to determine what to keep and what to delete. Sonar has had zero problems loading files from even 17 years ago, but plug-ins are a different story: no, I don't have the 32-bit version of Guitar Rig 1.0 still installed...
 
A while ago I figured out that any backup needed to include rendered, audio tracks of anything using virtual instruments and/or plug-ins, but this experience just reminded me of the importance of making sure everything exists as standard audio files in addition to whatever else is in the project, so I thought I'd pass that observation along.

Thank's for the tip Mr. Anderton!
 
That's precisely why I always backed up the pure audio of all song tracks, also instrument tracks (maybe different versions) to a separate song folder with some information about settings and so in a text file. I rendered also all extensive editings (Melodyne, Vocal Sync, volume automation ...) to audio files. Like that I could do the mixing in a new project that only referenced those audio tracks. If needed I just created another version of an instrument/audio track later on. In this way it has been easy to do backups and you can (re)mix in any DAW because you do not have dependencies.