I’ve searched all over to find why this is happening, any help would be appreciated. We just purchase our house and don’t have the money to refinish my sons bedroom. Of course right after we signed, there was a leak through the ceiling and we had to pull up the carpet. A month after the leak was fixed i spent a week cleaning the floors with mineral spirits and scraping old paint spots. I used a palm sander because i was scared of renting the big machines. Because some of the boards were a little warped i put a stain down lightly and wiped off right away to even things out. I got it looking pretty good. Then i applied matte finish varathane as directed but it crackled. It was as if parts of the floor were resistant to the polyurethane. I don’t know what kind of finish was previously on the floor and i know i didn’t sand down to bare wood. I just assumed it was a polyurethane finish and that if i buffed it up with the sander i could go over it with a water based poly. I don’t know how to attach a picture, but the best i could describe it is ‘crackled’. I’m disheartened because i have spend so much time on this floor getting it to look good only to have the finish ruin it.

This sounds like an adhesion problem. It may be from the stain not drying well enough or not completely wiping off all the stain. I use #2 steel wool to go firmly over the floor after staining.
You may be able to salvage the finish. Wait for it to cure and get hard, maybe 3-5 days with good ventilation and keeping the floor warm and ventilated. Then try a tape test, where you slit through the finish with a razor use tape pressing to get it to stick well, then ripping it up quickly. If the finish does not pull up, you can random orbit with 120 to smooth everything in the room and add another coat.

Thanks, i need to do that. I got impatient and sanded it today and it gummed up and now i have a big hole in my finish. I need to just step away from this project and come back to it. On to the front door, I’m a much better painter.