I should note after Step 3. when you go to about://chrome it says something like "Nearly up to date! Relaunch Google Chrome to finish updating.". It seems to be important that the update is downloaded but not yet running...

To aid people who are searching the bug tracker, Chrome displays when it can't find the Chromecast is "No Cast Devices Found".

Making this even stranger, going to chrome://cast/#devices in the problem browser finds the device even though View -> Cast does not. 

It's interesting that an empty profile fixes it for you.

Do you mind going into the settings for the missing device from chrome://cast#devices, looking up its IP address, and appending it to the bug?  If privacy is a concern I can mark the bug private to Chromium developers.

Chromecast information:

Firmware version: 1.30.111763
Country Code: GB
IP Address: 192.168.0.7

Mac's IP address: 192.168.0.6

@mfo... - if you mark the bug as private I will send over the MAC address too.

That shouldn't be necessary.   Do you mind filing a feedback report by right clicking on the toolbar icon -> Report an Issue?  Include this bug #.  We'll take a look and see if there is anything we can tell from it.

Feedback sent.

Hi, just to let you know Chrome has started showing a green arrow to indicate it's time to restart. I'll be restarting this Chrome instance in a day or two so if you need anything more let me know before then as it might be a while before this shows up again.

I've located the feedback report and we will look at it internally.

We have been noticed the same issue with Version 64 and 65 of Chrome OS.
We have just updated the chromebooks in our school district to version 64 and none of them are able to see any chromecasts when selecting the cast option. We have a tested this across Version 61, 63, 64, and 65. Only on versions 61 and 63 were we able to see any chromecasts under the cast option.

If I should create a separate bug or if you need any more info please let me know. I spoke to a google representative who recommended I comment on this issue.

Hi gdehoog@, are the Chromecast devices on public IPs? If so, in 64 we started disallowing connecting to Chromecast devices on public IPs due to security reasons. On Chrome 66 or later you can re-enable that feature by passing in --enable-features=CastAllowAllIPs in the command line, or by turning it on in chrome://flags (look for "Connect to Cast devices on all IP addresses"). We are looking to add an enterprise policy for this in Chrome 67.

The chromecasts are on public ip addresses.
I ran over to one of our classrooms with a private wireless network to test this with a new chromecast and everything works!
Thank you so much for the info.

The original issue likely has the same root cause as https://bugs.chromium.org/p/chromium/issues/detail?id=835017 and should be fixed by https://chromium.googlesource.com/chromium/src.git/+/86c3f0e1a5237885af245181b12b6f5f181571ef in M68.