Update known-issues.md

Author: uglide

docs/known-issues.md

@@ -1,13 +1,18 @@
-#### Why I get error : _db X (Loaded XXX of YYY. Error - XXXXXX)_
-You get this error if connection error occurred, or if you use unofficial port of redis for Windows - stable work of Redis Desktop Manager guaranteed only for latest version of Official Microsoft Redis port  ([https://github.com/MSOpenTech/redis/tree/2.6/bin/release](https://github.com/MSOpenTech/redis/tree/2.6/bin/release))
- 
-#### Black screen instead of Welcome tab on Windows under VirtualBox
-Remove opengl32sw.dll and Copy [this dll](https://github.com/uglide/RedisDesktopManager/blob/fix_improve_unit_tests/build/windows/installer/resources/rdp_fix/opengl32.dll?raw=true9) to RDM installation folder
+### Black screen instead of Welcome tab on Windows under VirtualBox
+Remove opengl32sw.dll and Copy [this dll](https://github.com/uglide/RedisDesktopManager/blob/5f99aa22aa84dc55b5c9858de28d68facd1c58b7/build/windows/installer/resources/rdp_fix/opengl32.dll) to RDM installation folder
 
-#### Graphical glitches on Ubuntu (RDM 0.7.9+)
+### Black screen instead of Welcome tab on Linux
+RDM starting from 0.8.0+ requires working openGL driver. Run `redis-desktop-manager` from terminal and search for error:
+`libGL error: failed to load driver: XXX`
+
+Also you can easily verify OpenGL support by e.g. running the `glxgears` demo application.
+
+**Solution:** Reinstall your graphics driver
+
+### Graphical glitches on Ubuntu (RDM 0.8.0+)
 It's the well-known problem of Qt Quick components.
 
-#### RDM crashed on startup (Windows & RDM 0.8.6+)
+### RDM crashed on startup (Windows & RDM 0.8.6+)
 RDM requires OpenGL 2.1 or higher to run. 
 
 What you can do: