My new possessions. Miltoniopsis, oncidium, and paph

[katrina]

I would not cut off all the roots. Sometimes the velamin ( spongy layer) can die off but the stringy root center still has some ability to transport water to the plant. When I have something like this, I gently slide the dead spongy layer off the roots but leave the "strings " and pot it up. At the very least, the " strings " will provide stability until new roots grow in. You will get new roots as new growths develop but, typically, the older growths won't make new roots.