VOEST D250 lathe.

I am having trouble disassembling the cross feed. It has a taper attachment and I have removed every screw I can find but I can't slide the crossfeed far enough in either direction to get it clear of the dovetails. The gib is removed.

Having photos would be good.
Cross slide or cross feed?
If I hazard a guess, I think that you haven't removed the lead screw and nut while you are trying to wined it off. Try liberating the nut from the cross slide before sliding it off, it may also be held with dowel pins.

Use caution if you are separating a nut from its lead screw, then ends are often not beveled and it easy to burnish the start of the thread on the nut making seize to the thread

I have a Voest DA 210; the same lathe except for scale. Have you detached the cross slide nut from the cross slide? The screw trough in the saddle is closed on all side trapping the nut so long as its attached to the slide. There are four screws holding the nut to the cross slide and two straight pins locating the nut in alignment. If the screws are removed the nut is still locked in place by the pins.

There's a window in the saddle bridge centered over the bed visible from underneath. Reinstall the nut attachment screws and snug them to prevent movement as you drive the pins. Move the slide so you can see the nut through the window by using a mechanic's mirror. The window is partly so oil and goo can drain from the trough and partly to allow passage for the nut pins as you drive them out for disassembly.

Knock out the pins through the window. Then remove the screws and slide the cross slide in the direction of the operator's station. If you've removed the micrometer dial assembly, the slide should come right out.

Now is a good time to add a cross slide clamp screw and beveled spacer in the gib side of the dovetail.

Be careful with the oddly located screws in the nut' bolt pattern. These are backlash/wear adjusters. There is a set screw close to force open the gap in the slitted nut and socket head cap screw that closes it. Having regard for hourglass worn in the screw, adjust the backlash to about 0.002".on the unworn portion..