diff --git a/doc/user_guide/en/install-linux.adoc b/doc/user_guide/en/install-linux.adoc
index 6461ac77e..bbd53b2b9 100644
--- a/doc/user_guide/en/install-linux.adoc
+++ b/doc/user_guide/en/install-linux.adoc
@@ -40,7 +40,6 @@ sudo dpkg -P wsjtx
 
 You may also need to execute the following command in a terminal:
 
-[example]
 ....
 sudo apt install libgfortran5 libqt5widgets5 libqt5network5 \
      libqt5printsupport5 libqt5multimedia5-plugins libqt5serialport5 \
@@ -73,7 +72,6 @@ sudo rpm -e wsjtx
 
 You may also need to execute the following command in a terminal:
 
-[example]
 ....
 sudo dnf install libgfortran fftw-libs-single qt5-qtbase \
      qt5-qtmultimedia qt5-qtserialport qt5-qtsvg \
diff --git a/doc/user_guide/en/install-windows.adoc b/doc/user_guide/en/install-windows.adoc
index 04b9785ce..b999c15e7 100644
--- a/doc/user_guide/en/install-windows.adoc
+++ b/doc/user_guide/en/install-windows.adoc
@@ -21,18 +21,30 @@ TIP: Your computer may be configured so that this directory is
      `"%LocalAppData%\WSJT-X\"`.
 
 * The built-in Windows facility for time synchronization is usually
-  not adequate. We recommend the program _Meinberg NTP_ (see
-  {ntpsetup} for downloading and installation instructions) or
-  _Dimension 4_ from {dimension4}. Recent versions of Windows 10 are
-  now shipped with a more capable Internet time synchronization
-  service that is suitable if configured appropriately.
+  not adequate.  We recommend the program _Meinberg NTP Client_ (see
+  {ntpsetup} for downloading and installation instructions). Recent
+  versions of Windows 10 are now shipped with a more capable Internet
+  time synchronization service that is suitable if configured
+  appropriately. We do not recommend SNTP time setting tools or others
+  that make periodic correction steps, _WSJT-X_ requires that the PC
+  clock be monotonic.
+
+NOTE: Having a PC clock that appears to be synchronized to UTC is not
+      sufficient, monotonicity means that the clock must not be
+      stepped backwards or forwards during corrections, instead the
+      clock frequency must be adjusted to correct synchronization
+      errors gradually.
 
 [[OPENSSL]]
 
 image:LoTW_TLS_error.png[_WSJT-X_ LoTW download TLS error,
   align="center"]
   
-* _WSJT-X_ requires installation of the _OpenSSL_ libraries. Suitable libraries may already be installed on your system. If they are not, you will see this error shortly after   requesting a fetch of the latest LoTW users database. To fix this, install the _OpenSSL_ libraries.
+* _WSJT-X_ requires installation of the _OpenSSL_ libraries. Suitable
+  libraries may already be installed on your system. If they are not,
+  you will see this error shortly after requesting a fetch of the
+  latest LoTW users database. To fix this, install the _OpenSSL_
+  libraries.
 
 ** You can download a suitable _OpenSSL_ package for Windows from
    {win_openssl_packages}; you need the latest *Windows Light*