Most of Time google chorome browser unable to install the plug-ins because of restricted by some other unknown programs.
For over come this issue we need to follow the below procedure.
step1 :- Browser -> Settings -> Extensions -> Get more Extensions
step2 :- Type plugin name which you required (seoquake) in Chrome web store
here, i choose seoquake plugin , at present we are not getting plugin in menu bar.
step3 :- click on seoquoke plugin you will get the pop-up window , in that select the “gmail” option
step4 :- here, you will get the path of the plugin shown below, copy that extension like shown in the image (except “=google”)
step5 :- In new window open the link “http://chrome-extension-downloader.com/”
In this website you will get the search area “Insert the web store url of the extension or just the extension ID:”
paste the extention code here which you copied and click on “download extension”.
step6 :- select downloaded plugin file and “drag and drop” in chrome extensions area for install