Thank you for the post.
I am able to open without error a file called UPPER.fmp12 in FileMaker Go 12.0.6 on an iPad 3. My testing shows that uppercase or lowercase letters in the file title make no difference.
FileMaker Go cannot be used for file conversion, so any files with the extension .fp7 will first need to be opened with FileMaker Pro 12 and any files with the extension .fp5 will first need to be opened with FileMaker Pro 11 and then FileMaker Pro 12 to be used with FileMaker Go 12.
Do the files with all uppercase letters in the title open in FileMaker Pro 12?
Could you provide a FILENAME.fmp12 file that will not open with FileMaker Go 12, so I may test on my end?
Thank you for the update.
Please check your inbox at the top of this page for instructions on how to submit your sample file to Testing and Development.