whilst working on project  , i opened  up another project, so i could copy and paste  midi from one to the other 
 i have done this many times before without a problem . i then closed the project i copied the midi information from
 
went to play the track and fatel error message came up.  could not close the project, after trying to cancel send report,
and got force shutdown window..3 programes were still running, the two projects,and kotact 5 i panicked and before i had a chance
my computer shut down..
 the project  i used to copy from  although still showing up in cakewalk projects opens up as a blank  no tracks, no snyths
no midi info no nothing ,just  blanked out areas ...if i hover over project file it says it contains 1.65 Gb but when i open it
the file contains cakewalk project file of 50.1kb..........and an audio file which contains four vienna instument files of around 400 GB
each , which open up media player ,some parts of this project are audible this way....there are other snyths in use ie dimession pro,
kotact 5 ect but no evidence of these  some how i have bounced to audio  and lost all midi info
   this is a disaster   as this project has all my musical ideas ... a friend suggested  system restore ..but i have no restore points
somthing was dissabled   please help if you can     phill
 

This has happened to others, over the years.
 
It is unfortunate that you did not have backups, as you are most likely toast.
 
Many of us have learned the hard way to back things up - in general that is a good idea.  Even more so when you could lose other people's data.
 
Bob Bone
 

There is really no helping you, if you never backed up your Sonar projects. So the million dollar question is, Did you back up your projects? 3 back ups are the norm, as you would keep 1 back back up of site in case of fire or theft and 2 back ups on different hard drives.
 
Hopefully you were backing up
 
Cj

Next time I suggest you buy something like an external 4Tb USB drive and a copy of Acronis TrueImage.
 
Only thing I can suggest is run chkdsk on your hard drive, and search your hard drive for *.cwp
I'm sorry this happened to you.

Try opening the project in Safe Mode, you may be able to salvage any audio and MIDI data that way. I have had issues like this from time to time with Kontakt, owing to the amount of RAM a lot of those libraries use.