Today at the office we ran into another application that mysteriously stopped printing. Our finance person occasionally uses an app that does a secure login to another system. Like RPM Remote Print Manager® ("RPM") this application's manual states that it sends data
"to the printer raw - without translating it, attempting to format it, or doing anything else to it."
It was this application which stopped working on her laptop, where it had been working for years.
One of our support techs paused her printer at the Windows spooler. He watched the print data accumulate in the printer folder, but as soon as he unpaused the printer, the data vanished, and nothing happened. We were sure from that sequence that the issue was the class driver for the printer.
When we have attempted to use a class driver with the Raw Print function in RPM, we got precisely the results described above. We assumed the driver was doing something to the data which rendered it incompatible with the actual printer. Now it seems that the class driver prevents raw data from even reaching the printer.
What is the cure?
Create a printer definition using "Generic / Text" as the driver. That is our recommendation, and it has worked so far for everyone who has tried it. That approach also worked with the situation I described at the top.
But wait -- here's an important update
We "cracked the code" on RPM working with Microsoft Class 4 drivers February 4, 2019, in version 22.214.171.1249. If you update your RPM version to at least that number, you will no longer have this problem.
Starting with version 126.96.36.1999 RPM can query the driver version from Windows and take the appropriate steps. This is for the raw print action.
The text print action has never had this issue.