Microsoft has no enough data about BugDigger so when you download BugDigger add-on for IE it shows a message like "BugDiggerIE-Setup.exe is not commonly downloaded and could harm your computer".
Click "Actions", select "More Options" and then "Run anyway". Or, simply open download folder and run the setup. (You need to exit IE before installing BugDigger add-on anyway.)
1) Right-click IE toolbar and make sure that BugDigger Toolbar is enabled. (If BugDigger is not listed among the available toolbars, it may not have been installed so try re-installing it first.)
2) Sometimes IE toolbar is minimized so BugDigger button is not visible.
Unlock the IE toolbar and drag the toolbar handle until the toolbar buttons appear.
Check your IE's security restrictions and policies. For example, if IE add-ons are disabled for the Intranet zone, BugDigger will not work when you open a site in this zone.