Recently bought an HP offijet pro 8600 premium. All is well as far as setup, wireless and general printing.

Only thing is when doing envelopes,. #10 work fine except sometimes the printer flips them and prints on the back, I think I fix that by turning off bidirectional printing. The other problem is with standard letter envelope, "sorry, can't find out the designator for them." The printer says the driver does not have this format. please update driver. I have the latest drivers, Any ideas out ther. TIA

Hmmm, what are you calling "standard"? To me, at least in the US, #10 (4 1/8 x 9 1/2 inches) is the standard size.

What is saying, "sorry, can't find out the designator for them."?