printing custom size envelopes in Word 2003

You may have to set up the same custom size in your printer's setup. Then you can choose the same size and not receive the error.

On a lot of printers, you must move the paper width slider to the edge of the envelope before you can print on it properly .. Also set the envelope in the proper way (word will show you which way it should be .. for example on my Lexmark X73, it goes in with the flap to the rear & left, envelope goes on the far right side of the paper feed slot)

I've tried with very limited success to get my HP printer (Deskjet 5650) to print on custom-sized envelopes.  My older model HP Deskjet that I no longer have handled the task beautifully, but this newer one kicks out the same error message that you have received.

Last Christmas I attempted to configure Publisher, Word, and then the printer software itself to handle the custom-sized envelopes that come with the MD Anderson Children's Art Project Christmas cards (6 1/2" length X 4 3/4" height).  I received mediocre results and went through quite a few envelopes before I gave up (last year was the first Christmas with the 5650 printer).  Previous years I had no troubles, as I always purchase the MD Anderson cards.

I happened to encounter an HP rep at CompUSA one afternoon (I live 5 miles from HP headquarters here in Houston).  I told him about my problems with the envelope printing as well as HP abandoning their "single-feed" envelope option on their printers, which would allow you to print one individual envelope for a particular document that you had constructed in Word (highlight the inside address, click on envelopes & labels, choose envelopes, put your envelope in the single-feed slot, press print, and your envelope was printed).  Now on the 5650 you get an error message if you place the single envelope in the tray that the paper size does not match.  The HP rep told me that HP had dropped the "single-use" envelope option because their engineers believed most people used labels now and that labels were more efficient.  Naturally, I disagreed.

I ended up printing labels for my Christmas cards, though, for I had nearly run out of envelopes battling with the software.

I didn't have any problems printing custom envelopes on my old HP either. Why do they have to change things?

It worked excellent on my old printer. I wasted more envelopes trying everything I could think of.

Guess I will have to go the route of the labels.

I totally agree.  Granted, this new 5650 prints faster and with more vibrant color, but for everyday usage, it's a far cry from the old Deskjet of years ago.

Now I just keep a box of labels next to my tray of extra paper and print individual labels (I work from the bottom up so that I'm always feeding in the form with labels at the top of the sheet).  Sometimes it's a hassle, but you have to go with what works and what gives you the least amount of stress.  Trying to figure out those Christmas card envelopes last year was a nightmare; I knew the labels would work for certain so I finally went with that.