Ahh so that's what's going on. I had assumed he had already booted into MacOS. I think he was at the Flashing Floppy icon. Now the instant eject makes sense.
Yeah try what technight has suggested. If the Mac was at the floppy icon asking for a boot disk, it decides pretty quick your floppy isn't bootable if it's able to read it. I think it would struggle for a bit if it was having trouble reading the disk due to an issue to the drive. Trust me, I had a disk with a bad track 0 and my Mac struggled for a few extra seconds before giving up on it.
The quickness it has at rejecting it means you most likely aren't prepping the disk properly for it to boot from. I had only one disk get rejected and that was due to bad sectors on Track 0.
Although interestingly, I was able to get rid of the bad sectors with a program called "Flobo Floppy BAd Sector Repair". Just something I found on Google recently when I had thought I was out of usable disks. (MacOS really hates disks with bad sectors. MS-DOS/PCs were a little more friendly to it since they could map them out as bad clusters. I don't think MacOS had a convenient way around them)
The program claims it recovers the lost space from bad sectors by doing what I believe is some kind of "unformatting" process where it resets the organization of the data tracks. I guess it re-magnetizes the entire disk? I don't know if it actually does that, but that's what the program maker claims it does. It did seem to work for me though. I used it on two disks I knew had bad sectors (and were reported as such with chkdsk. One of them I couldn't even format anymore due to bad track 0).
Afterwords I reformatted to FAT format using PC and rescanned with chkdsk. They both now work 100% it seems. (and the one my Mac would refuse to boot from was now bootable now!) Obvously the program says it won't fix disks that have physical damage like scratches on the oxide layer and age related deterioration of that layer. Usually you can see such damage by carefully opening the disk slider and rotating the disk surface to inspect it. I have a few that legit have physical damage to them. But two floppys that had bad sectors and had no apparent visible damage. So tried it on those two.
Although I've noticed that Basilisk II may not be formatting floppies correctly (The old version that can still access physical disks). It may be over provisioning them or something. I got a disk error when I attempt to fill up the last 60 or so KB on a disk. This happened consistently across two different floppies and was driving me crazy as it always happened when I tried to pop in one extra control panel or app.
Seemed too much of a coincidence. So I created a floppy image with HFVExplorer and opened that in Basilisk. It had less free space then my physical floppies. So I wrote that image to the disk with TransMac and now it looks like I have no problems with them now.
That program might be helpful in recovering vintage Mac disks that appear to have bitten the dust. Don't toss them just yet! They might just need to be remagnetised/unformatted. Obviously the above program will destroy existing data when fixing the disk, so this isn't something useful for trying to recover data on the disk. Mainly useful to make the disk usable as a storage medium again.
Yeah try what technight has suggested. If the Mac was at the floppy icon asking for a boot disk, it decides pretty quick your floppy isn't bootable if it's able to read it. I think it would struggle for a bit if it was having trouble reading the disk due to an issue to the drive. Trust me, I had a disk with a bad track 0 and my Mac struggled for a few extra seconds before giving up on it.
The quickness it has at rejecting it means you most likely aren't prepping the disk properly for it to boot from. I had only one disk get rejected and that was due to bad sectors on Track 0.
Although interestingly, I was able to get rid of the bad sectors with a program called "Flobo Floppy BAd Sector Repair". Just something I found on Google recently when I had thought I was out of usable disks. (MacOS really hates disks with bad sectors. MS-DOS/PCs were a little more friendly to it since they could map them out as bad clusters. I don't think MacOS had a convenient way around them)
The program claims it recovers the lost space from bad sectors by doing what I believe is some kind of "unformatting" process where it resets the organization of the data tracks. I guess it re-magnetizes the entire disk? I don't know if it actually does that, but that's what the program maker claims it does. It did seem to work for me though. I used it on two disks I knew had bad sectors (and were reported as such with chkdsk. One of them I couldn't even format anymore due to bad track 0).
Afterwords I reformatted to FAT format using PC and rescanned with chkdsk. They both now work 100% it seems. (and the one my Mac would refuse to boot from was now bootable now!) Obvously the program says it won't fix disks that have physical damage like scratches on the oxide layer and age related deterioration of that layer. Usually you can see such damage by carefully opening the disk slider and rotating the disk surface to inspect it. I have a few that legit have physical damage to them. But two floppys that had bad sectors and had no apparent visible damage. So tried it on those two.
Although I've noticed that Basilisk II may not be formatting floppies correctly (The old version that can still access physical disks). It may be over provisioning them or something. I got a disk error when I attempt to fill up the last 60 or so KB on a disk. This happened consistently across two different floppies and was driving me crazy as it always happened when I tried to pop in one extra control panel or app.
Seemed too much of a coincidence. So I created a floppy image with HFVExplorer and opened that in Basilisk. It had less free space then my physical floppies. So I wrote that image to the disk with TransMac and now it looks like I have no problems with them now.
That program might be helpful in recovering vintage Mac disks that appear to have bitten the dust. Don't toss them just yet! They might just need to be remagnetised/unformatted. Obviously the above program will destroy existing data when fixing the disk, so this isn't something useful for trying to recover data on the disk. Mainly useful to make the disk usable as a storage medium again.