I'm so mad I could spit!! What does it take to get STABLE SOFTWARE these days? I've been with Cakewalk since it's DOS launch before SONAR was but a glimmer. I had issues with version 6 so I VERY reluctantly moved to X1 and don't mind the interface IF IT WOULD JUST STOP TRUNCATING MY FILES RANDOMLY!!! I have Windows 7 Pro and build 534 of X1D but almost invariably when I'm editing a new MIDI or CWP file it JUST DIES on me after about an hour or two of work and often I don't even have an auto save file even though I have auto save on. Furthermore, I get a "recovery"file that's only 1K...
 
    Blue Bayou (Recover 13-11-17-21-56-14-745)
 
Yet won't load because it says "Oops! Sorry!! We truncated your file!!! In fact we truncate your file and trash your hard work AS OFTEN AS WE POSSIBLY CAN!!!"  WTF? REALLY? Is this what I get for DECADES of loyalty to this stupid shaky product!
 
UN-B-FREEKING-LIEVABLE!!
 
So do I finally wise up and jump ship to Pro-Tools or something else? Or is the crappy instability designed into the product so I have to fork over more $100s to get X2 and X3 and WTF ever!!????  Or do I just have a bad build and some kind soul out there will take mercy on me and lead me to a download of build 535 or something?
 

I've seen copies of the project files get truncated too. It's a bummer when it happens. I'm sorry you're losing work. I have no simple fix, but you have my sympathy.

Sonar X1 is now 3 years old. For $150 you have Sonar X3.
I've had X1, X2 and X3 and I've never had this although you have my sympathy.
Then again I've never had autosave enabled (I don't trust it, not even Microsoft products got this to work properly) and my system is stable. What I do instead is save frequently under a different file name and use the keyboard shortcut CTRL-S.
 
If it's really pissing you off that much please backup, wipe your PC clean and reinstall Windows, run the latest Windows updates and drivers, then install X3C. It's probably a couple of days work for you but I suspect it will be worth it in the end (and please update your footer so we at least know what system you are running).
 
Cheers....

Without knowing your system setup, tailoring your DAW buffers is an important thing to look at (and repeat when you make system changes). I do this with the demo project, and setting the I/O buffers too small gave me a "General Program Error" window on save... no crash, but no save either. Having them too high can be just as bad as too low. The demo file is a good candidate for this, since it is a full (and big project), and can be used by muting the final mix down track versus soloing it.
 
Tailoring DAW buffers:
Stay in ASIO mode first. There is some tailoring that needs to be done between the audio buffer and the I/O buffers. I had my ASIO buffer too high the other day and FastBikerBoy sent me back a nice PM on this:
 
   Start with the ASIO buffer at 128 (Preferences->Audio->Driver Settings->ASIO Panel...), and I/O buffers at 512 (Advanced Mode: Preferences->Audio->Synch and Caching)

1. Set preferred audio buffer.
2. Start playback.
3. If it drops out or other issues adjust I/O buffers. Try 512 for both as a starting point.
4. Repeat steps 2 & 3. Try adjusting buffers both up and down until happy. 256 jumps should do.
5. If after trying all sizes up to 1024 you still have issues go back to step 1 and increase audio buffer.
6. Repeat as necessary until you find the "magic" combination for your setup.

   The 128 audio and 512 for I/O was the "magic" combo for me at that time for the hardware I was using.
 
 

 X1D was a stable release and the chances are about 98% that its your system and its configuration that is causing the problem. So, perhaps if you were a little more specific about your system and your setup then someone could help

Naa wipe the OS start again, doesn't sound like there is a magic wand here. OP has been having issues since version 6 it seems... smells of a PC burning in software residue and loose ends. Unless the hardware is lacking or just getting too old.... But I do tend to agree, if you rant post the full detail. Otherwise it is just a rant.

I'm very strongly of the belief that 1) Sonar is way to picky about system configurations, and 2) something about Sonar's save routine makes it easier for projects to get corrupted than it should be. See these recent threads (there's a lot of input from Craig in the first one):
 
http://forum.cakewalk.com/X3c-project-corruption-AGAIN-m2929795.aspx
 
and 
 
http://forum.cakewalk.com/Exceptionally-frustrating-X3c-experience-m2923620.aspx#2923913
 
If you search these forums on "corrupt projects" or "can't open projects" and other similar keywords, you basically end up with a whole lot of posts around this subject going back years, and a lot of responses that basically say 1) "doesn't happen here, must be your system," 2) "that's why I never use autosave," 3) "that's why you have to use autosave," 4) "you have to Ctrl+S to save regularly," and most of all: 5) "it's your fault for not backing up your projects more regularly."
 
I just don't see that much energy on other DAW forums I frequent around these kinds of issues, and it's all over this forum. If Sonar's not directly at fault for all of these corrupt projects, then it's certainly not doing enough to prevent these issues IMO. I'm of the personal opinion that this is an area that deserves some major attention before X4, as there's just so many reports of similar problems for something not to be wrong.

Funckybot wrote;
"I'm of the personal opinion that this is an area that deserves some major attention before X4, as there's just so many reports of similar problems for something not to be wrong."
 
If it were it would be common and its not. In one case we have a non standard system because its being over clocked. I have projects going back to the Pro Audio days and none are corrupted. 
 
Generally I believe if this is happening it will most likely be due to an HD that is not working as well as it should or a bad HD subsystem. Drivers also play a role. Sonar itself can't be held responsible if its working with flaky systems.   

Has anyone NOT had a file that was fine during the last session but won't load anymore? I've had that problem with all the X series, across a couple of PC builds. It's not the hardware. Something  glitches and then the file is no longer usable. It doesn't happen very often to me, perhaps once a year, and has not happened yet with X3.
 
My own theory is that I have to close the project before I exit Sonar, instead of just hitting save and then exit. I've been doing this since it last happened in X2 and so far no more corruption.

ampfixer
Has anyone NOT had a file that was fine during the last session but won't load anymore? I've had that problem with all the X series, across a couple of PC builds. It's not the hardware. Something  glitches and then the file is no longer usable. It doesn't happen very often to me, perhaps once a year, and has not happened yet with X3.
 

Honestly, I think I've had that happen maybe 2 or 3 times in all the years I've been using SONAR - that's it.  So I'd have to agree with John that it's probably not a common problem in the overall scheme of things, at least when taking into account the entire SONAR user base (vs. forum members alone).   
 
However, I also agree with Funkybot that perhaps SONAR's save routine could be improved to make it more fault tolerant when something in the environment is not ideal.  Nothing wrong with that!
 
 
 
Edit: I usually (but definitely not always) close the project first before exiting, FWIW.