I would really recommend against opening your database's in 14 due to the crashes. The more you do it the more you have a chance of corrupting your database(s). And I really don't want that to happen to you. I recommend trying the trial of FileMaker Pro 17 Advanced, just to make sure your database(s) are still OK.
Hello,
FileMaker Pro/Advanced 14 will not work on 10.14. I highly suggest you take a look at the FileMaker and macOS 10.14 Mojave compatibility and FileMaker Pro 14 Technical Specifications | FileMaker
I would really recommend against opening your database's in 14 due to the crashes. The more you do it the more you have a chance of corrupting your database(s). And I really don't want that to happen to you. I recommend trying the trial of FileMaker Pro 17 Advanced, just to make sure your database(s) are still OK.
FileMaker 17 Platform Trial Software
I will also be moving your post to Discussions. The FileMaker Community Feedback and Information is more about the Community itself and not the FileMaker Product.
TSPlatypus
FileMaker, Inc.