How to recover text accidentally deleted?

Secondly, a minor problem, not so urgent: when I open a Libre Office document, it always says ‘Not recovered yet, start recovery, recovery failed, finish’ - but then the document usually appears. Can I get rid of this irritation?

Recover accidentally deleted text:
As long as you have not yet saved and closed the file, you can use ctrl+z (in Windows, Linux(?)) or cmd+z (?) for Mac.
Saving & closing of a file makes changes final.

“Not yet recovered…”
I would do:

  • Save the file after recovery.
    If this doesn’t help:
  • Save file with different name
  • Delete the file with the original name
    If this doesn’t help either:
  • Make sure your file saved with a different name
  • Re-set user profile; guideline is here: https://wiki.documentfoundation.org/UserProfile

How is your setting in ‘Tools’ > ‘Options’(‘Preferences’) > ‘Load/Save’ > ‘General’ > ‘Always create a backup copy’? If cheked you should find a backup of the previous state of any document edited in the ‘backup’ folder of your user profile.
You just have to copy it from there to your “workspace”, change the .bak extension as needed … voilà.

Be sure to note that the backup will not contain any changes made to the document during the most recent pass.

For additional information about the user profile refer to: https://wiki.documentfoundation.org/UserProfile

(From my experience: The default setting of that option seems to be “not checked”. I have to set it “checked” again after installing a new version. Hope you did.)