diff --git a/pages/merlin6/99 support/known-problems.md b/pages/merlin6/99 support/known-problems.md
index 0ed782c..505609e 100644
--- a/pages/merlin6/99 support/known-problems.md	
+++ b/pages/merlin6/99 support/known-problems.md	
@@ -10,33 +10,63 @@ permalink: /merlin6/known-problems.html
 
 ## Known Problems Summary
 
-| Topic                                                     |
-|:--------------------------------------------------------- |
-| [Paraview](## Paraview, ANSYS and OpenGL)                 |
-| [ANSYS](## Paraview, ANSYS and OpenGL)                    |
-| [Illegal instructions error](## Illegal instructions)     |
+| Topic                                                                                      |
+|:-----------------------------------------------------------------------------------------  |
+| [OpenGL vs Mesa](/merlin6/known-problems.html#opengl-vs-mesa)                              |
+| [Paraview](/merlin6/known-problems.html#OpenGL)                                            |
+| [ANSYS](/merlin6/known-problems.html#opengl-support-paraview-ansys-etc)                    |
+| [Illegal instructions error](i/merlin6/known-problems.html#illegal-instructions)           |
 
-## Paraview, ANSYS and OpenGL
+## OpenGL vs Mesa
 
-Try to use X11(mesa) driver for Paraview and ANSYS instead of OpenGL:
+Some applications can run with OpenGL support. This is only possible when the node contains a GPU card.
+
+In general, X11 with Mesa Driver is the recommended method as it will work in all cases (no need of GPUs). In example, for ParaView:
+
+```bash
+module load paraview
+paraview-mesa paraview   # 'paraview --mesa' for old releases
+```
+
+However, if one needs to run with OpenGL support, this is still possible by running `vglrun`. Officially, the supported method is
+NoMachine remote desktop (SSH with X11 Forwarding is slow, but also needs to properly setup the client -desktop or laptop-, where
+Merlin admins have no access or rights to it). In example, for running Paraview:
+
+```bash
+module load paraview
+vglrun paraview
+```
+
+## ANSYS
+
+Sometimes, running ANSYS/Fluent requires X11 support. For that, one should run fluent as follows.
 
 ```bash
-# ANSYS
 module load ANSYS
 fluent -driver x11
+```
 
-# ParaView
+## Paraview
+
+For running Paraview, one can run it with Mesa support or OpenGL support.
+
+```bash
 module load paraview
-paraview --mesa
+
+# Run with Mesa support (nodes without GPU)
+paraview-mesa paraview # 'paraview --mesa' for old releases
+# Run with OpenGL support (nodes with GPU)
+vglrun paraview
 ```
 
 ## Illegal instructions
 
-It may happened that your code, compiled on one machine will not be executed on another throwing exception like "(Illegal instruction)".
-Check (with "hostname" command) on which of the node you are and compare it with the names from first item. We observe few applications
-that can't be run on merlin-c-01..16 because of this problem (notice that these machines are more then 5 years old). Hint: you may
-choose the particular flavour of the machines for your slurm job, check the "--cores-per-node" option for sbatch:
+It may happened that your code, compiled on one machine will not be executed on another throwing exception like **"(Illegal instruction)"**.
+This is usually because the software was compiled with a set of instructions newer than the ones available in the node where the software runs,
+and it mostly depends on the processor generation.
 
-```bash
-sbatch --cores-per-socket=8 Script.sh # will filter the selection of the machine and exclude the oldest one, merlin-c-01..16
-```
+In example, `merlin-l-001` and `merlin-l-002` contain a newer generation of processors than the old GPUs nodes, or than the Merlin5 cluster.
+Hence, unless one compiles the software with compatibility with set of instructions from older processors, it will not run on old nodes. 
+Sometimes, this is properly set by default at the compilation time, but sometimes is not. 
+
+For GCC, please refer to https://gcc.gnu.org/onlinedocs/gcc/x86-Options.html for compiling options. In case of doubts, contact us.