Usually they ease up after a while, but I can barely budge one of them after washing it this week.

Just a guess...but the core of many vinyl windows is usually a wood based product. It sounds to me as though that wood core is getting wet from the washing...swelling in place...and making movement difficult until it thoroughly dries. It shouldn't be happening. It indicates the vinyl covering is not complete. There's a space somewhere. If you can locate the space...you might be able to seal it with a vinyl adhesive. Otherwise...be sparing with whatever liquid product you use to wash the windows...or wash them in place...without tilting them outward. I don't know what kind of guarantee/warranty came with the windows...but I doubt it's still valid. You might give a vinyl window contractor a call to come inspect the windows...but it'll probably cost you. The only concern I, personally, would have is that the core is rotting. That makes finding the moisture entrance an important task.

Thank you, Anne. That makes sense, but I don't think it could be happening. I use Sprayway to clean my windows, and use it sparingly, not letting it drip. I wipe it right off with microfiber or paper towels.

Our dirt road kicks up a lot of dust, so I appreciate being able to clean the outside of the windows. I keep thinking they must get off track somehow when I tilt them, but I haven't been able to figure it out.

I wonder if WD40 would help....? I'll have to read the can to see if it's okay for vinyl.

Have you noticed whether this happens after a rain storm...or during very humid weather? There's more than one way for moisture to get under the vinyl. When I had the same type window that you have...I cleaned them the same way you're doing. I wish I still had them. I have sliders now and I hate them because they're soooo difficult to clean.

I'm one of the rare humans who doesn't swear by WD-40 for everything. Better to rub a little Vaseline on the runner...or edge of the window. If it's a sticky groove...that will take care of the problem...and it won't do any chemical damage to the vinyl.

Can you tell if the window frame is moving?

The only other thing I can think of is that the casing is moving once you move the window out of the space that supports it. I think your house is delightfully too old to be settling...but who knows. We've had a very rainy year. If the wood casing is not solid...the easiest way to check is to take an ice pick...or similar thin sharply pointed tool...and try to insert it into the wood around the window. If it slides in easily...you may have a bigger problem than you want. I don't want to scare you by listing those possibilities.

Thanks to both of you, Anne and Maddielee. My son is always reminding me to Google any computer issues I may have, because someone else has surely had the same problem. Guess I thought I was the only one with uncooperative windows. :-)

I'm heading out today and will pick up Johnson's spray wax. I also need paste wax for something else, so that'll be my backup. I'll report back!

Alisande, wd40 will probably do more harm than good. I think what's happening, is time and the elements are breaking down the finish of the vinyl and collecting in the the contact points. the vinyl acts as it's own lubricant and with years of sun and dust it's acting like a glue. Try cleaning the surfaces and joints with mild soapy water in a spray pump bottle and use a tooth pick to get as much gunk out as you can and use the pump bottle with clean water to rinse. After it dries use LITHIUM grease, aka, white grease (auto stores carry it) to lube the joints. Work it in to the joints and surfaces and wipe off excess. Good luck.

Thanks, Jeff. I meant to add above that we've had a lot of rain lately, so that might be a factor as well.

Thanks, maddie. I wasn't aware of the Vaseline no-no! I use it on my frig gaskets and it's never done any harm. Keeps them supple and tight.
I appreciate this new knowledge. :-) I always learn something new here. Nice way to start the day!

and I wonder if the installer (dh) has done it correctly....lol...

Susan, I know, I just don't get them lined up totally straight sometimes, after folding it in to wash.

Are you sure, you get it back up totally straight?

Mine are all vinyl too.

Moni

I can't say that I'm 100% sure, Moni, but I'm aware that it's easy to not get them properly lined up, so I guess all I can say is they look straight to me. And I'm big on straightening pictures that hang on the walls. :-)

Maddielee, the question doesn't show up at that link anymore. It's said to be under review.

I couldn't find Johnson's spray wax, so I'm in the process of painting a thin film of paste was on the tracks of one window. I'll wipe it in a few minutes and see what happens.