Thank you for your post.
I am unable to replicate the issue using FileMaker Pro Advanced 14.0.5 on a 27" iMac with Mac OS X 10.11.3.
What other applications are open at the time you are quitting FileMaker Pro? Does this issue occur when no other applications are running?
Under the Window menu, are there any files listed under "Show"? If so, how many files? What are their function?
Do you have any plug-ins installed and enabled? If so, what plug-ins?
Let me know if there is anything I can do to replicate the issue.
Thanks for the reply. I have discovered that this is an issue with a plugin I am beta testing. I think it's safe to close this issue.