How to remove inaccessible file from Recents List

Opened a file over shared network at home. Now on travel and file is inaccessible, but LibreOffice keeps popping up a dialog saying “cannot find the network”. I want to purge the Recent List. Have tried History Manager extension, but it will not install because of the popups. Cannot start LibreOffice at all! Do I need to reinstall?
System MacBook Pro OSX 10.11.3
Thanks in advance,

See this posting I cannot delete obsolete ' recent items'

It modifies registrymodifications.xcu in the user profile.

Does someone know if setting the ‘PickListSize’ to 0 (zero) in the ‘Expert Configuration’ (available via Tools/Options/LibreOffice/Adavanced) also can do what the OP is needing? (This way the setting might easily be reverted when appropriate. The ItemList of the file history [100 items] will not be afflicted. This was a wrong interpretation of what I saw. A few additional tests showed a rather dubious behaviour.)

(I cannot test myself at this time.)