Apple has taken a sandboxing approach to Adobe's Flash plugin. This causes the editor to fail to import images from Microsoft Word content.
With the default configuration on Safari, when pasting content from Microsoft Word images will not be imported.
When pasting Microsoft Word content that contains images, the following prompt appears:
Pressing Command + V will normally insert the images correctly. Instead, an error is shown:
You can configure Safari to allow Flash to run with no security restrictions, but this involves changing a setting in Safari's preferences. This will allow the editor to function correctly. Please note that this is a per-workstation change. To properly configure Safari please perform the following steps:
1. In the Safari menu, click Preferences.
2. Click the Security tab, then click Plug-in Settings...
3. Click Adobe Flash Player on the left, then click the dropdown next to your site that includes Textbox.io (this example uses https://textbox.io)
4. Select Run in Unsafe mode.
NOTE: in Safari 10 the text changed to a checkmark with "run in safe mode". In addition it is no longer shown unless the option key is held when clicking to open the dropdown.
5. Select Trust on the security warning that appears.
Note: This has to be done for each website where the end user accesses Textbox.io.
6. Click the Done button to apply the new settings.