Has anyone had any success getting File Maker Pro 12 work on High Sierra? If so, how?
do a search on the Community, there are many questions on the subject.
It's the first OS X version that breaks FM12. You will have to update to FM16 or downgrade to Sierra.
As others have alluded to, FileMaker 12 is not certified for macOS High Sierra. The only versions of FileMaker Pro that have been tested and therefore certified for use with macOS High Sierra are FileMaker Pro 15 and FileMaker Pro 16.
See here for more information
FileMaker platform compatibility with macOS High Sierra
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