Import large Fx bookmarks to portable Fx 2.0.0.4 crashes

I had a large (545k) bookmark file in my regular Fx which I wanted to import to my USB stick and edit to remove stuff that I didn't want on the stick.
'import' in Manage Bookmarks in Portable Fx crashed.
Copied bookmarks.html to the stick and fired up portable Fx. As soon as I opened Bookmarks, Fx crashed.
Seems to be a size limit on the Bookmarks file.

found a workaround.
Installed Portable Fx to my HD, fired it up, imported the Bookmarks file OK, editted it down to what I wanted, copied this bookmarks.html (about 250k) to the stick. Works fine.