any PlugIn's involved?
If though, deactivate all Plugs and try again.
Thank you for your post!
FileMaker Pro 10 was not tested to work on OS X 10.12 (Sierra), so this could be some form of compatibility issue. You might see System Requirements for FileMaker Pro 10 and FileMaker Pro 10 Advanced.
efficientbizz made a great suggestion in trying without plugins.
If FileMaker Pro 10 was installed before upgrading the Operating System (such as OS X 10.10 to 10.12) then a reinstall may be a good step to try.
You might also confirm whether this happens in a New File as Data Corruption can occur over time and cause strange issues like this. If you feel your Solution may be damaged I'd suggest seeing What to do when your file is corrupt.
I hope this helps!
Sent from my iPhone
FM11 seem to work with my macOS Sierra. Maybe you can get a cheap update, in case you hesitate to overhaul your solution for the new file protocol introduced with FM12.
As we know, FM12 hit every record with the amount of bugs, FM13 shows a annoying screen flickering with every "go to Layout", for FM14, I can't confirm yet if the printing bug with portals is really fixed with FM14.0.6.
I can highly recommend FM 15 with great performance, reliability and most of bugs fixed!
It's worth the money