Hi, I've found a way to set my X Windows resolution to any value in my Fedora Core 5 guest OS. I thought it could be interesting to let you know. STEP 1 In the Guest OS configuration, add the resolution to the custom resolutions (video settings) if it's not a standard one. As an example, I've added 1680x950 (I got a 17'' Mac Book Pro). Otherwise just go to step 2 STEP 2 Start the OS, and edit /etc/X11/xorg.conf (with root priviledges) Ideally make a copy of this file so you can rollback the change... The file path and name is as in Fedora Core 5... It might be a little different on other distributions. Locate the Section "Monitor" Keep the lines : Identifier,VendorName,ModelName (you can set them to anything you want) Comment out all other lines (except of course the EndSection one). Now, go to : http://zaph.com/Modeline You only need to enter the Horizonta/Verticall pixels you want (so for me 1680 and 950) Then you MUST set Vertical Frequency to 60Hz (I read that somewhere) Then click on "calculate" This will give you something like this (result for my 1680x950@60Hz): # 1680x950 @ 60Hz, 58.86 kHz hsync Mode "1680x950" DotClock 121.02 HTimings 1680 1712 1840 2056 VTimings 950 953 956 981 EndMode Copy it and paste it before the EndSection line of the config file. Now, go to the Section "Screen". Change all the Modes lines to add the new resolution as the first entry (you can only leave that resolution if you want). In my case: Modes "1680x950" (one line for 16bits depth, one for 24bits depth) Save the file STEP 3 Reboot the Guest OS -- That worked perfect for me... I hope it will for you !! -- IF SOMETHING GOES WRONG You should still have console access to your Guest OS. In that case, just revert the xorg.conf changes and restart your Guest OS.