When starting Microsoft Outlook, several error messages appear with the title Custom UI Runtime Error (in the English Outlook version, the error message is Custom UI Runtime Error). The actual error message may vary in detail for each display.
Similar error messages appear when composing a new email.
Update to version 5.2 of DRACOON for Outlook, as the problem no longer occurs here.
Disable the corresponding option in Outlook, as it is intended for developers only:
- In Outlook, click File, and then click Options.
- Click Advanced in the left navigation bar.
- Scroll down to the Developer heading.
- Clear the Show add-in user interface errors check box.
This is not an error message, but a harmless warning message intended only for developers (programmers). In fact, the warning message appears only if the Show add-in user interface errors option is enabled in the Outlook options. This option is intended to help Outlook extension developers identify non-functioning UI elements in Outlook extensions.
The message can be ignored.
The warning message appears not only with DRACOON for Outlook, but with each Add-In, which integrates itself into the "New Mail" menu ribbon of Outlook. Because the user interface for the whole Add-In is defined as a rule already with the Outlook start about a single included XML file. But at this time the "New Mail" ribbon does not exist yet, so Outlook issues this warning if this option is enabled.