New problem I've been experiencing.
 
Every time I save or save as my current project, sonar seems to freeze for a second before attempting to save, and gets a little stuck when saving. This usually happens on the first save, then on the second save it will usually just freeze and stop responding.
 
Any ideas why this may be happening?
 
(Sonar 8, Windows Vista)
 
Have had no problems like this previously.

It's now crashing on every/any save, and I have a deadline approaching rather quickly. Help much sought and much appreciated!

This time it did the whole freezing thing, but I waited, and it simply error messaged "Failed to save document".

Even sometimes just clicking on the 'save as' can cause it to crash.

I just opened a different project, and that saves fine, no errors or freezing.
Using the same old synths and plugins I usually use, so that lessens the chance of it being them...

I think some of the audio files I've used are aiff, but audio folder shows them as wav (so obvs Sonar resaved/converted). Can't think of what it is other than Sonar just not liking the project, which is ironic as it's one of my better ones.

check your windows logs for error messages.

I have 82 gb free.

But Sonar just gave me a error message about memory.

Really don't get whats going on. Have made bigger projects than this.

The last project file is about 3.78MB, other projects I've had are less then this, by greater than half.

Something unusual about this project file size?

More likely a windows issue like a problem with the hard drive.

You could have a badspot on the drive. Try renaming the project folder, make a copy of it and try to open/save the new copy.

82 Gigs is your Hard drive not your memory. 
And that sounds full by today's standards. Audio really likes a nice clean 7200 rpm drive with no fragments and 50% headroom. . 
Back everything up to a external drive before you do anything else. 

You should put your computer specs in your signature, it makes it easier to figure stuff out when we know what we are dealing with.