Last night, about 6 hours into an 11 hour flight to KJFK, I got a slow motion CTD such as I've never seen before. In fact, I've never had a CTD, I think, on this newer PC running FS9 and never had a CTD with the PMDG Queen.I had the PMDG 744 2D cockpit up on the 24" LCD primary and on the secondary 19" LCD I had 4 windows open including a SPOT 02 view showing the UQueen in all her glory on about 8x10" size. I clicked on the windows "X" spot to close that SPOT 02 window and immediately, the secondary monitor went to standard DELL blue desktop while on the primary monitor, from the top of the screen all the way to the bottom it scrolled slowly (about 10-12 seconds) from the sim to the DELL blue desktop as well. It was a rather elegant CTD, like the end of some movie or whatever.Then, silence....!There was no sign of any overheating of the PC or any hardware distress and the flight had been proceeding normally, with periodic saves (phew!) by me, and I was approaching the coast of southern Greenland. After the CTD, I rebooted Fs9 and then ran the saved file of the flight from near before the CTD point and all was well when I closed down 1 hour later for bed-time and had flown way past the CTD point geographically. I have limited add-on scenery but it's all elsewhere globally and I've checked my scenery folders for the right AFCAD etc carefully in the recent past to ensure it does not create a CTD like this.Anybody hazard a guess as to what must've happened?Or was it perhaps just a random, bad, post-Icelandic moment?Jonathan

Also look at any USB devices you have connected to the computer. I had a Goflight device that would intimately disconnect and reconnect while I was flying and it would cause my FS to run at .05 FPS and the sim would crash soon after..

Yeah, thanks, I know what you mean and I have experienced some slowdowns and freezes of FS9 with GF equipment, but never a CTD like the one last night. I have reconfigured all of my GF devices so that the critical ones like the MCP plug directly into a USB 2.0 port in the PC which keeps it stable and freeze-free. Jonathan

Well, the very slow refresh of the screen means you ran out of memory and it was using virtual memory. You may have a memory leak with some software on your computer. Check you memory periodically as you fly and see if the usage is increasing. You have the 9.1 patch installed?Hope that helps a little anyway :)