I have an extensive collection of fonts (60,0000+). Several hundred of them will crash my system when I open one of them in Finder (double-click the suitcase). I picked one at random for some serious examination.
I looked at my sample with many font tools. My latest tool was FontDoctor (v5 and v7). FontDoctor reported "no problems found" with my font. Yet the crash persists.
Please suggest a tool that can do a thorough job of investigating and repairing my corrupt fonts.
Well it turns out that NO tool can repair this font. So I wrote my own.
The problem turned out to be a bad 'hhea' table. The values for Ascender, Descender and LineGap were all zero.
Once I changed these values to something reasonable, the font appeared like magic and my system no longer crashes with a "Divide by Zero" error.