Changes in Chrome 71 break Gmail.

I've complained about Chrome automatic updates before. I actually stayed on outdated Chrome 45 for a long time because I really needed NPAPI support to perform certain tasks. 

But few months ago I decided to bite the bullet and "live a normal life". So, I enabled Google Chrome updates and crossed my fingers. It worked for some time. I got the awful "modern UI" and managed to turn it off. I got the automatic Chrome sign-in that nobody actually wants and Google retracted later. And I was able to turn it off too.

But now Chrome cannot open my Gmail account. WTF?

Can't sync to account.

When logging into Gmail it just pops up this message "Can't sync to account. Request cancelled."

What is this white box at the top of the webpage? Is this message coming from the webpage or Chrome itself?

Compare it to the message coming from Pandora webpage:

Can you spot the difference? I can't. New and "improved" Google Chrome UI is misleading you.

Windows has nice APIs for showing all sorts of dialogs and message boxes. They there for a reason - to provide consistent user experience. Just use them!

Well, it turns out that this message comes from Chrome itself. You click "OK" and you're thrown back to the login page. Occasionally, Chrome shows "too many redirects" error or forwards you to the page explaining that your cookies are invalid and you should try deleting them.

I deleted cookies. Did not help. Switched off my adblocker. Did not help. Opened "Developers Tools" and looked at the Network tab. For some mysterious reason some of the requests fail.

Being paranoid I checked my computer for malware. Didn't find anything.

Then I tried using my good old trusted Chrome 45.. Surprise, it just works! 🙂

Solution.

This problem only occurs if you have set a #account-consistency flag in Chrome flags settings to "disabled":

Identity consistency between browser and cookie jar
When enabled, the browser manages signing in and out of Google accounts. – Mac, Windows, Linux, Chrome OS, Android

#account-consistency

...and then upgraded to Chrome 71.

Since this setting is used to stop automatic sign-in in Chrome, I had it set to "Disabled" after Chrome 69 update.

Somewhere between versions 69 and 71, Chrome introduced a new setting in the UI called "Allow Chrome sign-in". By default this value is set to enabled.

Allow Chrome sign-in
By turning this off, you can sign in to Google sites like Gmail without signing in to Chrome

When these two settings have conflicting values, everything blows up in a spectacular manner. 😡

Fix is really simple - open Chrome settings, and disable "Allow Chrome sign-in". And everything magically works again.

Conclusion.

It took me good 4 hours to figure out what was causing the problem. And that's the main reason for making this post.

Yes, Chrome team has a big ugly disclaimer that changing Chrome flags can break stuff. Yes, my configuration is not "out-of-the-box-standard". But still, Chrome should not break functionality on auto-update, no matter what configuration I have.

Auto-updates and rapid release of bugfixes is not a substitute for proper testing. It might sound strange for those who grew up on mobile devices where daily updates are the norm. But trust me - humankind didn't get to the Moon or Mars by writing shitty code and fixing later. We got there by writing quality code.

Have fun and write good code!