We are facing the same issue with one of our clients. I don't think the official Odoo statement, that the way different mail clients render content is out of their control is OK. Outlook is one of the major mail clients and since we have been working with email campaigns a lot with other tools, I know that a high level of compatibility can be acchieved with varous tricks.

So, I submited a ticket to Odoo support, to start testing what they are getting out of their code compilers. I am preaty sure I will get a generic response from support but I am writing this also publicly so that someone at Odoo will strat giving this higher priority.

We don't need more fancy features in the mailing app, but we do need those that are there to be stable and well tested. So please @FabienPinckaers if you think that the mailing is an important app as I do, please give this issue a high importance rating.

Hi there,

I'm using email marketing app now and facing the same issue. My newsletter email on outlook get all messy and disformatted, elements resized oddly and it's not responsive. 

Can you tell me how  saving an Outlook Template will help? Can I upload that template into a newsletter on Odoo? How do I do that?

Thanks in advance

Same issue with several customers

Odoo does not seem to be willing to solve the issue

I had this issue. It might not be related to Outlook. In my case it was editing the email in Odoo with the Safari browser. This could be verified in the Mail Debug tab (activate Developer View to see this). Editing the shot email with Chrome magically fixes the issue.

I'm having the same issue, the only thing I was able to do is to use another app"stripo"

I build the email in stripo
export to html
edit the code (in developer mode) in the odoo mass mailing module
paste the code

It works but it's a bad solution, as I can't edit in odoo after that.

I wish the odoo editor was better, its really not ok that outlook is not supported

I'm in version 15, I tested in version 16 and I have the same issue, the web editor was improved, but the mail editor seems to be forgotten. 

Go to File and select Save As.
Under the file type drop-down menu in the Save As window, choose Outlook Template.
Name the template accordingly. An example is [Company Name] Monthly Newsletter Template.
Click Save to finish and close the template.

Hope You Find This Useful,
Peter