A little over 40 years ago, while we were still using TRS80's at the
college, the purchasing agent was sleeping with a vendor, and got us
RoyType HD diskettes, instead of what we asked for (Verbatim Datalife).
When used in the TRS80s, it would format and write without showing errors,
but minutes later, the disk was blank again!
Do NOT use HD diskettes to write DD formats!
(yes, on 3.5", you can use a high quality HD diskette to get a poor
quality DD diskette, but on 5.25", you usually do NOT get away with it.
Can you finish your use of the disk before it fades away?)