It (Lucidchart integration) works fine with Google docs etc but I just cannot get it to work with Word and ppt - even though I have upgraded to Edge and use the latest version of Chrome. Your assistance here os really appreciated - thanks

Hi Sudscor thanks for posting. You are seeing this message because we no longer support Internet Explorer 11 which older versions of Windows and Office use as the default browser to load the login screen for our Office add-ons. The default browser used by the desktop Office apps can't be changed on older versions of Windows and Office; it is chosen by the versions installed even if you set a different browser as the default in Windows settings.

Updating your operating system to Windows 10 version 1903 or later AND your Office apps to Microsoft 365 version 16.0.11629 or later should resolve the problem as you will be able to use Edge as the default browser in Office apps. I'm sorry for any confusion this might have caused. Please let me know if you have any questions. 

so it's no longer compatible with pre-365 versions of office?
could you update the compatibility list of the add-in to only Office 365 then?
because it still lists Office 2013-2019 and they all use IE11.

Hi Michael

Thanks for your comment.

We will verify the accuracy of the compatibility list and make any update if necessary.

Thanks for bringing this to our attention!