When you encounter the "Icon? files cannot be backed up" error message while backing up your Eagle library, there's no need to worry. This is because "Icon?" is a special file generated by the macOS system to store custom folder icon information. Eagle uses these files to manage your custom folder icons, making it easier for you to identify different resources in the application.

Why does this problem occur?

"Icon?" files have special properties that many backup tools cannot handle properly. This doesn't indicate a problem with your library, but rather a compatibility limitation of the backup tool.

Solutions

You can resolve this issue using the following methods:

Check backup tool documentation: Review the official documentation of your backup program to see if there are options to handle or ignore such special files
Delete "Icon?" files: If the backup tool cannot resolve this issue, you can choose to delete these files

Open Finder
Press Command + Shift + . (period) to show hidden files
Find and delete the Icon? files within the .library folder
Try backing up again

Important Notes

Deleting "Icon?" files will not affect your library functionality. These files are only used to store icon information, and Eagle will automatically regenerate them the next time you use the application.

How to resolve the "Icon?" file cannot be backed up prompt when backing up a repository?