It may indeed be the case that we are talking about two different problems. My Zebra is used to print RFID cards and each card takes long enough to print that sending the next file in the queue is not a problem.
It may be different with printing labels...
Yes, my use-case was printing labels with text for packaging.
And if you need to print hundreds of labels, speed matters
Also an older version of the program worked fine.
Does anyone have any idea what the problem is and how it can be fixed?
You didn't mention the versions of Lazarus + bitness (32/64bit) and fpReport you are using.
When I run the app on a computer that doesn't have the zebra printer connected everything works fine.
Was printing to a different printer (i.e. Print to PDF) possible on that same machine with a Zebra printer connected to it?
Just tried to print the report to a PDF printer and could print 12000+ pages without any problems in Lazarus trunk 64bit with LazReport 1.0.
So I'm not sure if it has to do with the label-dimensions.