... the program the CPU load increases by a large amount, as in :- 2001_171937_140000000.png The PC is a dual core 3.2Ghz P4 with 4GB ram running XP. Sometimes the system fan speed ramps up as an indicator that the CPU is getting hotter when performing certain tasks such as preparing a printout. I noticed tonight that if you leave the program in certain menus/dialogue boxes such as editing sleepering data or shoving timbers it also puts a heavy load on the CPU. A little later I managed to get this message :- 2001_171944_160000000.png closely followed by :- 2001_171945_500000000.png I only had the single track item on the go with no background images or anything like that. I had been playing around with rail lengths trying to figure out how to get 30' track panels with 12" joint sleepers and 10" for the rest of the panel( 32mm O scale) and had tried to save the current settings into one of the custom locations. The memory available when it gave the error was about the same as in the Task Manager 'shot' above. ...