Mysterious Track Rendering problem

[RJWlaw@aol.com]

Running very latest T6.

Have several audio tracks that do this:

Each track has three or more separate non-contiguous audio clips of acoustic guitar. Basically the choruses.

None of the individual tracks will render when given the "Render Track" command.

There are no plugins on the tracks, and each track is routed normally -- direct to the interface outs 1 + 2 -- nothing fancy going on with this aspect. No mute or solo buttons engaged. Volume and pan positions normal.

I clik on the red button and nothing happens (The render dialog box does not appear, and I get the "Tracktion is not responding" message up in the title bar. Then the translucent white overlay screen look presents itself. Have to Ctl-Alt-Del out of T6

If I copy and paste the clips from a track into a naked new edit that I open while keeping the real edit open, they render just fine. (In fact, this was my workaround -- copy and paste into a blank edit, render, and copy and paste/replace rendered track back into the real edit.

Tried rebooting, creating a new empty track in the real edit and copying/pasting into the new track, but same behavior.

Maddeningly, other acoustic guitar audio tracks in the real edit rendered just fine -- just like normal.

There is nothing unusual about the tracks or the clips on the tracks that will not render and causes the odd "Tracktion is not responding" message up in the title bar.

Anyone experience non-contiguous clips in a track causing this behavior? Ideas?

Win 7 pro, 64-bit, 24 GIG Memory, T6-64 bit, 3 largely empty SSD disks, etc.