Dear all, I have quite simple repro where I am not able to boot into MS-DOS image (it is also described by this question from this year but not answered / https://forum.parallels.com/threads/ms-dos-6-22-image-will-not-boot.349177/). Basically, I created VM with one disk connected to IDE 0:0, booted woth MS-DOS 5.0 disk image. Run FDISK, created partition on the drive and then run FORMAT C: /S to format it. System is successfully transfered from A: floppy and I can validate it with running ATTRIB C: as seen on screenshot. Then I disconnect image from drive A: and reboot VM and I receive massage there is no boot device. As summary: VM has 1 Disk Disk is set to IDE 0:0 Disk C: is formatted with /S options and validated that MS DOS OS is on the disk When A: is disconnected machine does not boot into C: drive. Petr
Just for curiosity; MS-DOS 5.0 works but MS-DOS 3.11 not. Using steps in the initial question above, booting into MS DOS 3.11, running FDISK to create partition, setting partition Active, formatting using FORMAT C: /S will be hanged by the sceen shown in the attachment. C Drive is recognized as bootable but loading OS it hangs when OS boots. I am experimenting with some really old development tools so this is for my educational purposes. It seems that Parallels is not able to boot into MS-DOS 3.11 so if this may be something that may be causing another compatibility complience with old software it may be worth checking.