I have a problem quite similar to that described in a posting from 2018 in the Excel community: https://techcommunity.microsoft.com/t5/Excel/Can-t-add-User-Form-in-VBA-project/m-p/153619
After a hardware change, I tried to use my makros and tools which I programmed using Office 2017 in Office 365. It works in Word, in Excel and in Access - but it doesn't work in Outlook. Whenever I try to insert a user form, I get the error message mentioned in the subject.
I opened a new discussion as my situation (works for most of the office programs but does not work for one) is slightly different and Outlook is concerned. All the libraries mentioned in similar cases also in other communities are installed correctly (just to be sure not to miss something, I add some screenshots).
Any hints or new information since 2018?