Web browsers furthermore do not hinder a user to bookmark a website for a second time. Some may visualize that a bookmark already exists but none will stop the user from bookmarking a web page multiple times.

Bookmark Sentry for the Google chrome browser is a browser extension that can scan all bookmarks for dead and duplicate links.

The extension scans all browser bookmarks automatically after installation. This can take some time depending on the number of bookmarks and the folder structure.

The scanner displays the scan progression in the extension’s options. It shows the bookmark that is currently scanned, the percentage as a bar and number, the last scan, next scheduled scan and the number of problems found (which either means dead or duplicate bookmarks).

Scan results are displayed on the very same screen after a scan for duplicate or dead bookmarks finishes.

The extension displays status codes and text to make it easier for the user to identify the underlying problems. Each bookmark can be removed individually by clicking on the X at the front of each result. There is no option to delete all at once. Links are clickable to manually recheck the bookmark in question.

Bookmark Sentry will scan all bookmarks once a month by default. It is possible to change the interval to another or switch to manual checks only. The only other available preference is the time between connection scans. The default time is 10 seconds, reducing it will increase the scan speed.

Bookmark Sentry is a helpful extension for the Chrome browser. Most users are probably fine with running the extension once to check their bookmarks and disabling or uninstalling it afterwards. Only heavy bookmark users may need to use it regularly.

Update: The add-on has been removed from the Chrome web store. A Chrome extension alternative is not available. Windows users can use AM Deadlink instead which supports the Chrome browser as well.

Would not it be great if there was a tool that checked the bookmarks automatically for dead links and duplicate entries ? A tool that would be able to read and check bookmarks in many browsers such as Firefox, Internet Explorer, Opera and Mozilla ? I assume you answered the above questions with yes, if that is the case AM-Deadlink might be the exact program you would like to take a look at.

Am-Deadlink is freeware, just download and install it on your computer.  You have a drop down menu on the upper left corner when you start the program where you chose the browser you want to check. You sometimes have to navigate to the bookmarks folder of that browser manually and select it, but that should not be a big deal.

Now you can check the appearing bookmarks and find duplicates. If the link is dead a 404 error most likely appears in the line of the bookmark. You can now delete that bookmark if you like or leave it there and check later again. Those errors also appear when a website moves host and that process has not finished yet for example. It is always a good idea to check it more often before you delete an entry.

AM-Deadlink has the ability to backup the bookmarks as a zip file, there is unfortunatly no option to import bookmarks from one browser to the other directly. You may export bookmarks in a universal format and import them later through your browser though.