I sometimes attach a document to an email (webmaila.juno.com). Unbeknownst to me, LibreOffice changes all my documents to zip files, which my recipient can not open. I do not want any of my documents to be saved as zip files.
The ODF file format has several internal containers, and is packaged using the zip algorithm, so technically your files are a kind of zip files. However, they should be stored with the proper odf extension which specifies a document type (e.g. “.odt” for Writer files).
Internet Explorer is known to recognize content format when service does not specify content-type header info for the download, and to replace extension accordingly. I am not sure whether his may also happen at upload.
If the cause is as indicated above, there are several paths to try to rectify the problem:
- If you are using the Juno service, use a non-Microsoft browser for accessing your email (anything other than IE and Edge).
- change to a service with up-to-date content handling. Juno has gotten a somewhat bad reputation lately. Try a free gmail account and see whether the same thing happens still.
- Advise the recipient to use a non-Microsoft browser, or preferably access their email through mail client software.
If you are certain that LibreOffice is causing this (i.e. you see the zip extension before you enter “mail context”), it is a bug. Try to download again and perform a fresh install.