Yesterday I tried to print some documents using the networked printer in the department. The first time I tried this, it was about half an hour before I went to retrieve the print-out. When I got to the printer there was no sign of it, but the document had gone from the printer queue so I thought it might have disappeared due so some sort of error.
Later in the day I tried to print something else. I can see the printer from my office door so I watched to see if the lights on top started to flash. Nothing happened so I deleted the document from the print queue and decided to use the other printer, which is down the end of a long corridor. This other printer worked ok. Nobody else had problems with the first printer so I suspected my computer and thought a re-boot might help.
This morning, after turning my computer off overnight, I tried to print something out using the first printer again. I sent the document to the printer and watched for the flashing lights. The printer leapt into action so I walked over to retrieve my print-out. I was surprised to find it had printed out the missing document from yesterday morning as well as the document I had just printed.
I don't know where this first document was hiding. It can't have been in the printer because other people had successfully used it after me. It wasn't visible in the printer queue of my computer. For some reason it only started to print when I decided to print something else, so it looks like it was hiding somewhere in my machine. Very puzzling.