Hello! I have been messing with some really old pcs, a 386DX and a 486DX2 ... both have the same award BIOS btw.. It appears that in both machines 3.11 won't start if a UMB manager is activating UMB blocks. This happens with both EMM386 and TheLastByte managers... You can get 3.11 to load even with the above managers if you use the "DOS=NOAUTO" value on config.sys, without any HIGH/UMB parameters so DOS loads low. Ofcourse you don't get UMBs even with the managers running but 3.11 boots. I also tried adding EMMExclude=A000-FFFF to [386enh] or the /D:x switch, neither helped. I know this is old stuff but if you have any tips I will appreciate it Thanks in advance! edit: I forgot to add, I am using DOS7.1 (from 98SE) with a FAT32 drive... not so stock but it worked perfect with rloew's fat32 patch on a different 486 that had PCI slots and a way newer BIOS...