Problem exporting new font

Lately i moved from fontlab to Glyphs and as I’m moving on with my existing projects I’m getting this message while trying to export my arabic font…

Problem with ttfautohint.
No glyph for a standard character to derive standard width and height.
Please check the documentation for a list of script-specific standard characters,
or use option `–symbol’.

any clue what’s wrong here?
thank you in advance for the great work

Lets see what clues are in the error message. It says that ttfAutohint can’t find something. That mean that you export you font as TTF with autohinting enabled. And that your font has no Latin glyphs (that are needed by the autohinter to determine the dimensions of you font). There are two possible solutions: give the autohinter the information it needs by adding a custom parameter to the instances that sets the default language to Arabic. Or export as OTF (that might give a bit nicer rendering in Indesign).

Thank you so much Georg
i will just export without autohinting for now to test till i am done with adding the latin glyphs matching the arabic then i will fix and do the hinting once and for all
thank you for the reply and the great work