I wonder sometimes when people complain about their printer being a piece of crap, when they don't mention if they've tried anything else besides call for service. With any printer the stock run through it is by far the biggest factor in the results achieved. The envelope itself is, 99% of the time, the problem. It should not a process where a customer picks the envelope first, then forces the printer to be changed to run that exact envelope. The printer design is relatively fixed. No manufacturer designs a printer not to work. Find the right envelope to match the printer you own. If it won't run one brand, try a different one. If a certain shape of flap doesn't work, find one that does. There are thousands of different envelopes out there. There are hundreds of types of #10 envelopes! I've listened to customers complain that the machine was junk, because the same size envelope, but with a different flap shape didn't run at all, but the previous shape flap ran thousands with no problems. The machine didn't change, the envelope did. No manufacturer has ever stated that their machine will run every envelope ever created, they just state that it will run envelopes.