Hi Sabuj, Installing Chimera over an existing Chimera (i.e. specifying the same installation directory) is asking for trouble. I'm not sure the Chimera installer will even allow it, and if it does it may first delete the entire contents of that directory. I realize though that updating Chimera and keeping your separately installed plug-ins is a pain. The solution I use is to not put those plug-ins in the chimera/share directory. I use a separate directory outside the installed Chimera tree called "chimera-plugins" in my home directory. I put all Chimera plugins in there. I added this directory to the Chimera search path using menu entry Favorites / Preferences category Tools, then press the "Add..." button an the bottom under the "Locations" panel and add this chimera-plugins directory, then press the "Save" button so that this search path is saved for all future Chimera sessions. It is saved in your Chimera preferences file (~/.chimera/preferences on Linux) so it is not deleted if you update Chimera. This a good solution for individual users, though not so good for a Chimera installation used by multiple users since then each one of them has to add the chimera-plugins directory. I'll add this advice to the Chimera Experimental Features (plug-ins) web page installation instructions. Tom