Pfaff Expression 3.5 repeatedly shows "Sensormatic buttonhole foot connected. Please remove foot" while I am sewing with a regular foot and a regular straight stitch.

SOURCE: How do I change the stiches?

You can do all of these stitches by using different combinations of your stitch selector, stitch width and stitch feed knobs, for instance, on the panel I can see on your machine:

http://www.jo-ann.com/joann/product/images/52659.jsp?CATID=cat3122&PRODID=prd11333

Stitches 1, 2 & 3 are straight stitches, centered, left and right. Really basic stuff, not different stitches at all. 4,5,6,7 & 8 are zig-zag stitches of different widths. 9 is the widest zig-zag (no. 8) on a finer stitch length, etc...

I think you should try and get an instruction manual for your machine. After a lengthy search of my usual manual sources, I've determined that that this may not be so easy. I think you should contact White on their 800 number and let them try and help you... 1-800-331-3164.

If you found this helpful, please vote generously as I receive nothing other than acknowledgement for my time.

SOURCE: How do I change the stiches?

The brother website has a users manual for it that can be downloaded. Use this link to get it:

http://welcome.solutions.brother.com/bsc/public/us/us/en/doc/manual_index.html?reg=us&c=us&lang=en&prod=hf_ls2125eus&type2=5&flang=English&dlid=

SOURCE: Singer 7462 buttonholer

generally most sewing problems are due to sticking parts because of non usage as =you have stated or because the tension has been not set right. what I suggest is that you take the time to do some cleaning of the machine like what bis pointed out in your manual use a light weight mineral oil to wipe the moving parts with, but not too much. also adjust the tension of the foot so there is pressure on the material as to move it while sewing. after all the cleaning and adjusting rethread the bobbin and make sure it is seated properly also rethread the need and make sure the thread moves freely from the spool. this should do the trick. please rate this

SOURCE: Pfaff 1222's 3 stretch stitches sew wrong and backwards only.

It sounds like the feed mechanism needs oil.

SOURCE: SINGER 7422 28 STITCH 2 BUTTONHOLE INSTRUCTION MANUAL

http://www.singerco.com/accessories/manuals.html