Issue when opening a Glyphs 3 file


I am writing on the forum today because I have encountered strange behavior in Glyphs 3. The same behavior was reported by “T Derkert” In his forum post titled “Error dialog on startup and when opening Plugin Manager.” Link: Error dialog on startup and when opening Plugin Manager.

I am creating a new post about this topic because the culprit of the same strange behavior might be different in my case.

When opening a file in Glyphs 3, I am greeted by an error saying that data cannot be read because it isn’t in the correct format. That said, the file still opens normally, and closing the error message doesn’t cause the file to close with it.

“T Derkert” identified the cause of the same problem to be add-ons he was using with Glyphs. That said, I don’t think I am using any add-ons at all. Furthermore, I am at a loss for possible reasons for this could be happening to me.

Any help troubleshooting would be much appreciated.


Can you try to start without plugins. Hold down the Option + Shift key when you start Glyphs.

Hi Georg,

Thank you for your response. I’ve decided to err on the side of caution just in case the error message indicates that one of my .glyphs files is damaged or corrupted. I plan to reinstall Glyphs and revert to an earlier backup of the same .glyphs file.

Will Glyphs be reset to its default state if I remove it from my applications folder and reinstall it? Would I need to remove any cache or other data elsewhere?

I’ve also noticed that Glyphs warns you when you open a file saved with a previous version of the software. Are there any steps I need to take to make an older file compatible with the newest version of Glyphs? If so, what are they?

Your assistance is much appreciated!


Can you show the actual error message you are getting?

I don’t think that will make a difference.

No. As already mentioned, reinstalling the app will most likely change anything. There are two places that you need to clear when you really, really need to (and I’m pretty sure you are not in this case) clean up the installation: The preferences file “~/Library/Preferences/com.GeorgSeifert.Glyphs3.plist” and the Application support folder: “~/Library/Application Support/Glyphs 3”.

Could you send me that file that I can check what’s wrong with it?

Hi Georg,

I don’t feel comfortable giving people my source files. The original error message I got was the exact same one that “T Derkert” had in his forum post. Link: Error dialog on startup and when opening Plugin Manager.

I tried reinstalling Glyphs 3 on my computer. The previous error message no longer shows up. That said, I am observing new unexpected behavior that I will share with you (Screenshots below):

  1. When Glyphs 3 finished downloading, the icon was crossed out in my browser downloads.

  2. I was warned that the Glyphs 3 file in question was saved with a previous version of the application. This happened after I opened the file with a fresh copy of Glyphs 3 that I downloaded from the website.
    Screenshot 2024-05-14 at 11.47.55 AM

IMPORTANT NOTE: I hit “OK” on the modal warning me that my file was saved with a previous version of Glyphs. Next, I saved my file and closed it. There are no longer any errors or warnings when I reopen the file again. I suppose this indicates that things are ok now. Are there any other things you’d recommend checking when considering the information that I’ve given you?


Can you post a screenshot of your error message?

But it still runs?

That happens if you update Glpyhs. That is totally normal. It is a precaution, not a problem. Sometimes an update changes the behavior of Glyphs slightly and some people need to know if they open a file in another version.

Hi Georg,

The original error message telling me something like “data cannot be read because it isn’t in the correct format” no longer shows up. Therefore, I cannot send you a screenshot of it. I am trying to figure out why this error showed up before but isn’t showing up now.

Glyphs 3 seems to run fine after I redownloaded it (I have no idea why the icon was crossed out in my browser downloads).