Can no longer save LibreOffice docs after Fall Creators update

I’ve been using LibreOffice 4 for months maybe over a year.

When the Windows 10 Fall Creators update update came out I installed it.

I had some LibreOffice files that I’ve been using for months at least. After the Fall Creators update I was able to open them but not to save them.

I got this error message:
Error saving the document posts, comments, etc:
General input/output error while accessing D:\Users\Angus\Documents\notes.odt.

which is a “No Entry” icon, OK is the only option, click OK & the window reappears
click OK and then:

Error saving the document notes:
General Error.
General input/output error.

Then the only thing I can do is exit the file without saving.

I think I noticed these files: ODS# File, ODT# File, which may not usually be present:

.~lock.scratch1.ods#
.~lock.notes.odt#

I deleted them and it had no effect.

I uninstalled LibreOffice 4 and installed version 5. I’m now on:
Version: 5.0.5.2
Build ID: 55b006a02d247b5f7215fc6ea0fde844b30035b3
Locale: en-GB (en_GB)

This made no difference to my inability to save existing ODS and ODT files. Some of the files are big and some small.

I was able to copy the contents of the unsavable files to the MS equivalent and carry on using them but as I’m renting MS Office and would prefer not to, I’d like to get back to using LibreOffice.

Anyone else have this inability to save LibreOffice files or problems with the Windows Fall Creators update?

The problem was most likely caused by the recent Windows update and https://support.microsoft.com/en-us/help/4046851/windows-10-controlled-folder-access-windows-defender-security-center

It was resolved using the information is this thread: https://ask.libreoffice.org/en/question/138666/installation-failure-warning-1909-internal-error-2902/