If this is a bus error, i'm assuming card issue, so Im currently taking it out and checking and cleaning contacts on the simms, it came with 4x256k, then I'll try again. Could it be a software app issue, such as i'm getting the wrong app pkg for it? When i unstuffed it the main prg ibm-pc 286 icon, if i choose get info both versions say copywrite orange micro either 1988, 1990. I know ast sold out to them but mb I have the wrong version, meant for the orange micro version, vs. the ast one? One last thing, when i use the get info on the 2.x version of the pc prg, not only does it show the cpywrite of orange micro, towards the bottom I can adjust the mem min/max such as default of 640k then 1024k max. If I try lets say 384k to start and max @ 640k, the prog doesnt even run it gives and error about min 384k or less so it wont run and bomb. Finally I don't think its an insufficient mem issue on the mac as it does have 8mb installed on the mainboard.