I regularly exchange files over email with clients. Every time I open a document, place the cursor and start typing, everything is ignored, because a message across the top of the screen says “This document is open in read-only mode”. It’s then necessary to click the button "Edit Document"to unlock it.
How do I completely disable this so I’m able to edit all files immediately on opening, for all the Libre Office products?
Just save your file to some local directory before opening it. Most probably this is preventing from making changes, while the file still is in some temporary cache directory of your email application. You may(!) lose all your changes, if you close the application owning that directory. For that reason: There is no way to circumvent that.
And in fact: The write protection is done by the email client and hence LibreOffice can’t do anything here. Just checked a download of a file using Firefox and here is what I get in the temporary Firefox directory (r means: read, but no w(rite) here in -r-------- )
ls -l
insgesamt 12
-r-------- 1 opaque users 9497 7. Mai 19:18 16080385029129446.ods
That’s what happens when Firefox passes the link to an downloaded file via os functionality to LibreOffice (and a similar thing happens with email). So, even if I’d instruct LibreOffice to edit the file, I can’t save to that location and need to save to another place anyway.
Primarily this is a reminder that the document is not yet saved (permanently) into your folder structure or collection of files. Depending on your email-client (a browser or a dedicated email-application), the location of the file is in some temporary directory, which normally will be erased the moment you close that application. Temp-folders can also easily be overwritten. LibreOffice may even not have adequate permissions in that location to do its work; write lock-files, take backups, etc.
On this very site, there are several questions about data-loss due to exactly this scenario. So, the preferred way is to first save files from email to a sensible location, and then work on them. Anything other is far too unreliable.