Fixing incomplete measures? Can't write tuplets over barlines?

I posted something similar under the Engraving topic, rather than reposting I'll just copy and paste the link here: https://musescore.org/en/node/365529

Then I found this: https://musescore.org/en/node/335324
Which suggests I copy and paste the original XML import's notes into a different MuseScore file. When I try to do that, it exits out of the file. I figured out why it does that eventually; I can't write tuplets over barlines. So now I'm stuck trying to figure out how to do that. It's a piece with 997 measures so I'm wondering if there's a way to just erase all the bar lines (based on https://musescore.org/en/node/19889 and https://musescore.org/en/node/278554 ) so that I can paste it and figure out the time signature for the individual measures later, but then I'm wondering, even if I do that, will I get the incomplete measures again when I try to export it? Is there a way to check that? Is there a simpler way to correct the incomplete measures for a piece with this many measures?