My personal favourite from the era of the floppy disk comes from the time I spent supporting an accounts and payroll suite. In the eighties remote support was not a luxury we could afford so we often had to travel to the customer premises. But some customers data files were small enough to fit on a floppy disk, indeed many customers used machines without hard disks. These machines had to drives and we always taught customers how to make backup copies of all their data and program disks.
We tended to teach grandfather, father, son backups. This was usually sufficient if data became corrupted. We would tell the customer to return to the previous backup. We seldom had an incident where at least one of the backups wasn't good, even if the customer had to re-input a few days worth of data.
On occasion however there would be a situation where even the backups were corrupt. The file format was a linked list and on more than one occasion I had to read those lists in a text editor and fix the links by hand. Often I could achieve this without the loss of any data.
One day I got a call from a customer reporting an error message suggesting a corruption in the linked list. She confirmed that the computer had been switched off without saving the data. This made things simple, it should be a case of going to the most recent backup.
I asked her to try the backup copy, but she admitted that she hadn't made a backup copy since she'd started work at the company as nobody had ever showed her how. So the must recent backup was several months out of date.
I should at this point have realised that my next suggestion was unlikely to have the desired outcome. I informed her that I could probably fix the problem, but the cost of my traveling to their office to carry out the repair may be prohibitive. I could however repair the data if she were to send me a copy of her data disk.
The very next day an envelope arrived containing, as you've probably guessed, a photocopy of a five and a quarter inch floppy disk.