as far as I know, it's because of acrobat - there must be other postings concerning this issue here. Try to boot in secure mode - the dialogs should be back again
This is one of many acknowledged bugs that can be found in the Known Bug List thread here in the Report an Issue section of the forum.
It can also be downloaded as a database file from: https://www.dropbox.com/s/jt09b82i0xijbu3/FMP%20Bugs.zip
The cause turned out to be a DLL assigned to the AppInit_DLLs key in the registry, under:
The value was set to btpload32.dll which is part of Beyond Trust, a system we use for allowing certain app installers to run on users' machines even though they don't have local admin rights. But I think the issue with Adobe is similar (just a different DLL). This key specifies a DLL that is loaded with every process in Windows and allows hooking into each process.
When I cleared that registry key, FileMaker worked. But I can't leave that key cleared since it's part of our IT network security setup.