Google Chrome does not open custom protocols

Question

I've been using a simple mechanism for registering a custom URL protocol on Windows 10, allowing a link in our web application to launch a local program on the client computer. For example :

<a href="mycustomprotocol://scan/0&1608962&1&248">Launch program</a>

In regedit, the protocol is registered here :

Ordinateur\HKEY_CLASSES_ROOT\mycustomprotocol\shell\open\command

with a value like :

C:\Program Files (x86)\MyProgram\MyExecutable.exe "%1"

It has stopped to work on Chrome 63. Nothing is shown in the dev console nor in the network tab, whereas it still works well on Firefox or Microsoft Edge for example.

If I delete my user profile in C:\Users\johndoe\AppData\Local\Google\Chrome\User Data, then click my custom link again, Chrome asks me if I want to launch my local program but nothing happens when I click on the "open" button.

Any though ? Is this feature now blocked by Chrome ? Can this be unblocked ? Thanks for your help.

Answer 1

Turns out that I was missing two keys in the registry. It was okay for Edge but not for Chrome. Here are the keys to add at the level Computer\HKEY_CLASSES_ROOT\mycustomprotocol\ :

Name                   Type                       Data

(Default)               REG_SZ                URL:My Fancy Program

URL Protocol       REG_SZ