There is a major bug in SED that, as you type in SED, the system's resources gradually decrease. In my 2D game, for example, which is nothing more than panels and a 10,000-line script, when I'm typing up a long script, I watch my resources go from 52% free to just 14% free in about an hour. The fix (temporary) is to close SED, wait a few seconds for the resources to replenish and reopen SED.

A quick way to get SED to crash from this is to run the engine through SED, press control+escape to return to windows then use control+alt+delete and end the task of the engine. Then, in SED, type even one character and wait. The resources drop 9% in just 2 minutes and they will continue to drop as long as SED is the active window. I reported this crash bug quite a while ago. In my case, I was using a breakpoint_on instruction (for debugging) and when I pressed Esc to exit the engine, it didn't work, even after several tries. I had to resort to closing the engine in a remote way (control+escape to get into windows to do that, learned this accidentally two years ago) since there was no other way to close the engine (I was running in full screen so I couldn't click the X in the corner or right-click on the window in the task bar to close it that way).