how to delete and re-install Mail

The reason why this can not be done is because Mail is built into and is part of the Operating System.

It could not be removed nor installed as a Standalone Reinstallation.

If there is a specific issue with Apple Mail application, perhaps if the user describes the issue we maybe able to assist.

Hi @espiekermann,

FWIW, From this info you posted in response to P. Phillips, about an attachment issue, it could be that the file size of the attachment exceeds your email providers limit. You might want to check what their limit is then compare that to the size of files you're trying to attach.

You're welcome.

espiekermann wrote:

the issue is that mail attachments don’t work. Instead the message says that the attachment is being uploaded. I do suspect that this is caused by another app, but cannot find out which one. Sometimes the issue is gone after re-start but happens again later

Q - I do suspect that this is caused by another app, but cannot find out which one. "

A -Based upon the description above >>

Download the Application Etrecheck directly from the Developer.

This is a Diagnostic Tool that makes no changes to the computer.

It makes a coherent and readable inventory of both the Hardware and Software used on the computer 

The application is free or paid from added features. 

The Report will Not Reveal Any Personal Information. 

Post back the Full Report - copy and paste - >>>> using the Additional Text Icon ( 3rd Icon to last ) <<<<

It's not possible to reinstall Mail. You would have to reinstall macOS to get a new copy of Mail.