So this might be one of the strangest problems that I have ever seen in FileMaker.
We have a FileMaker 15 file with 300 layouts. All of these layouts were created back in FileMaker 10, and all of the layouts are using the Classic theme. On all 300 layouts, the font for all the fields and field labels throughout the entire system was either set to Verdana (12 point) or Lucida Grande (10 point).
The file is not corrupt... it passes the consistency check and the recovery with no problems found. This file is being hosted with FileMaker Server 15.0.3 on OS X 10.11.6, and the client machines are all running FMP 15.0.2 on OS X 10.11.6.
Everything has been working fine with the file for ages, and then suddenly, just a few hours ago, all 300 of the layouts have actually CHANGED the fonts on all the layouts! All the fonts throughout the entire system have changed! What was formerly Verdana 12 point is now Arial 12 point. and what was formerly Lucida Grande 10 point is now an "empty" font (no font name shows up in FileMaker) at 10 point.
The font changes have taken place AT THE LAYOUT LEVEL. If I go into layout mode, and click on any field, the "new" font and the "new" font size is what is shown in the "Format > Font" menu. So it's not some sort of "superficial" font substitution of text that's happening here... these font changes have actually taken place AT THE LAYOUT LEVEL. Crazy, I know!
Last night’s backup of this file? Everything is fine at the layout level. Today’s file? Everything is wrong at the layout level.
It seems as if somebody completely changed the theme for the entire file, but:
(a) Within the last 7 days, nobody has logged in as the [Full Access] user — which is the ONLY user that has access to modifying layouts.
(b) Every layout is still listed as the Classic theme, which can’t be modified. So nobody has modified the theme at all. The style throughout the system is still set to “Default style” as well.
Even if we stop hosting the file on FileMaker Server and open the file LOCALLY on any Mac's desktop, the same problem remains. This problem happens on all machines. Every single layout has the "new" font and "new" font size for all of its objects. Whether the file is opened remotely or opened locally, the "new" fonts are showing up on all the layouts in layout mode.
Font Book has all the right fonts installed, there are no font conflicts, there are no duplicate fonts. And this happens on all machines. The actual layouts have all been changed.
So now, we have 300 layouts that all have the wrong font for all the fields. I suppose that the quickest fix to this would be to duplicate the Classic theme as a new theme, get the new theme set with all the fonts that we want, and then apply the new theme to all 300 layouts.
But I'm extremely concerned about how this could have happened in the first place, and what can be done to prevent this in the future. Ideally, if there is some other way to fix this without creating a new theme, that would be incredible.