Some times we might have got typical question around how to get the particular dll from assembly folder. Because when you open that assembly folder it doesn't allow you to do normal operation as in windows explorer. Solution: Click on start button Select RUN Enter the following path to the directory C:\windows\assembly\GAC_MSIL An window will get open.All the folders you see in that window are dlls . So select the required dll folder and open it by double click on that. Inside that one more folder will be there. Within that folder you can get your dll. Simply right click on that and copy . Paste it in required file system Hope this may help some one during site upgrade Thanks pradeepa achar