Many problems with Sonar X3 Producer

Hi!
For some time now, various weird problems are occurring.  I don't have experience with any other DAWs, so I'm not sure as to what is going on.  I am experiencing the following:
 
-Sometimes, the software crashes
-Playback stopping for no reason some time after working without a problem.
-Frozen tracks (VSTi like kontakt, omnisphere and Era) look unfrozen, and don't play back (even though nothing is muted)
-Midi events change without touching a track: extra notes are introduced, seemingly randomly.  These do not show up in piano roll, and can't be removed.  The only way to fix this is by completely deleting the midi data for the track, and replacing it with the midi data from an earlier saved version (even though no changes have been made by me in this time).
-Volume of certain tracks changes drastically after clicking 'reset midi and audio', to max volume or even louder (impossibly).  In the vsti interface, despite this, the volume is still in the original position.  When changing it in the interface, volume jumps back down and can be controlled, but after clicking 'reset midi and audio' again, it glitches out again.
-Clips start playing at the wrong time (multiple measures before the clip even exists)-Sometimes projects are pretty long to load, and crash upon finishing loading.  Other times, the project loads but playback is not possible.  In this case, when I open an older file without closing sonar, playback can work fine for those files.  This crashing upon loading can happen with very simple projects as well (~5 vsti tracks, less than 3 minutes long)
 
The most complex thing I've done so far in the DAW was a project with 17 tracks, consisting nearly exclusively out of kontakt libraries (komplete 10 ultimate and various orchestral 8dio libraries), Engine (era medieval II, and forest kingdom II), and Omnisphere 2.
 
I am never running above 60% cpu usage (i2500k at 4.5ghz, 60 degrees C ), I have 16gigs of ram and all my libraries are installed on a samsung SSD850pro (1TB).  All unused samples are purged out of Kontakt.  HDTunepro does not detect any problems with my harddrive.
 
I am using a nektar Impact LX49 controller.  I plug it into a usb3 slot.  I also have some hard-drives which automatic backups are made onto.  Maybe this can damage files while I am working in a project in sonar?
 
Currently I am only loading one instrument in each instance of Kontakt, because I like using the prochannel EQ and different effect plugins on each instrument.  Anything wrong with this?
 
Sampling rate is 96k, buffer size is 1.3msec/128samples.  I use Quadcapture as an instrument interface, with latest firmware.
 
Can anybody help?  The FAQ is not very helpful since these problems are difficult to reproduce and are not consistent. Weird stuff just happens.
 
The best,
Peter

Thanks for your quick reply!
I'll do that for now, and will see if problems persist.
Currently, I've exported the audio I had, and started a new project with that, appending what I have.