Is Gmail log-in broken under Safari 13?

Yes it is. Do NOT under any circumstances install Safari 13. It will break all your gmail accounts in Apple's Mail app and there is no official fix to this nasty nasty bug. You'll waste hours and hours trying to figure out what's wrong and it will drive you completely nuts.

The only way to solve this problem is by re-downloading Mojave 10.14.6 and re-installing it on your Mac. By doing this Safari will go back to 12.1.12. You might still have to re-authenticate all your gmail accounts but it will work easily under Safari 12. Just follow the prompts and everything will go back to normal.

Safari 13 is seriously destroying lives right now. Don't come even close to it, I've made that mistake and had to pay with three or four days of my time looking for a fix until I figured out it was the **** browser update that broke all my gmail.

You're welcome.

Are you running any anti - virus programs? Using a VPN?

Try setting up another admin user account in System Preferences/Users & Groups to see if the same problem continues. Please post back on whether or not this worked. Also try the Safe Mode. Please post back on whether or not this worked.

Isolating an issue by using another user account 

Safe Mode - About

If it works in the Safe Mode, try running this program when booted normally and then copy and paste the output in a reply. The program was created by Etresoft, a frequent contributor.  Please use copy and paste as screen shots can be hard to read. Click “Share Report” button in the toolbar, select “Copy to Clipboard” and then paste into a reply. This will show what is running on your computer. No personal information is shown. If the log won’t post, try posting it in Pastebin and provide a link in a reply. After pasting the report in a PasteBin page, go to the top of the page, and copy the address in the URL bar. Paste that in a new reply.        Pastebin

Etrecheck – System Information

This appears to be a bug in Safari 13. There have been multiple posts by people having the same problem.

If you want to, you can send Apple feedback. They won't answer, but at least will know there is a problem or a suggestion for change. If enough people send feedback, it may get the problem/suggested change solved sooner.

Safari Feedback

I worked with Level 2 support and this is a confirmed bug that the agent was able to re-create. I gathered diagnostic information for them and they were going to escalate to engineering for an evaluation.

No it isn't. That suggested 8 steps "solution" is way more complicated and time consuming than a quick Mojave re-install. Especially for people who run multiple businesses with multiple gmail accounts that are now all broken. The simplest way to deal with it is by doing this 2 step fix:

1 - Re-install Mojave 10.14.6

2 - Do not upgrade to Safari 13.

Done.

Even though I don't access gMail via the Mail application, I access the service via Safari and yes, after updating to version 13, I cannot log onto my gMail account. On screen a dialogue box told me to disable cookie, after a few trial & error I gain access by going to Safari preference, then the tab Websites and turn off Content Blockers related to "account.google.com".

See if that works for you at least via Safari; if so, try adding the gMail account as you originally intended to see if that would work. Hope this helps.

Question: Suppose I do reinstall 10.14.6 , get Safari 12 in the bargain, then am able to complete authentication in Safari. Can I then install Safari 13 without having to complete the authentication in Safari again, this time, of course, unsuccessfully?

That would be my understanding. The auth to Google should not be undone by a Safari update.

I should have been fine, except I added dual factor to my Google account which forced re-auth on all devices. Oh, the poor timing.

@rjkmadison,

I experienced the same problem, not with Gmail, which I don't use, but with Google Calendar. The problem occurred when or after I upgraded from macOS 10.13.6 to 10.14.6 over this past weekend. Everything was running fine in 10.13.6, Calendar was happily accessing my Google Calendar without clamoring for authorization ... and it was running Safari 13, albeit probably a version for High Sierra. After the upgrade of macOS I distinctly remember having to approve the update of Safari. I didn't notice until a day after updating Safari that I had a problem with Calendar accessing the Google calendar. I don't know whether that was the case immediately after 10.14.6 was installed, or whether the Safari update caused that. If the upgrade to 10.14.6 triggered the request to complete authentication, then I should have paid more attention and attempted to do so immediately. I guess I was just too focused on completing the upgrade, incl. any software updates, before deciding what the upgrade might have broken.

Hard to say which of the 188+ contributions describes the solution. The last entry simply echos a recommendation in this thread to reinstall Mojave from the App Store. One entry above that claims that setting Google Account | Security | Less secure app access to On somehow solves the problem. I tried that. Trying to use the Google Calendar account in any way on macOS 10.14.6 thereafter still offers the option of invoking Safari to complete the authentication, and clicking that button has the same effect as previously, i. e., no login page for Google appears in Safari.

OK, I had this problem with Google Calendar. Once I updated Safari the "Open Safari" button really worked, I logged into Google and agreed to the all the dire warnings about authenticating macOS. After that, I had to restart the Calendar app in macOS. Maybe, eventually, Calendar would have polled Google, but restarting the app forces that.

A request to the author of this thread:

Apple has updated Safari. The updated version has solved the problem for many followers. Please test it. If you agree, set the status of this thread to Solved, so that people who still experience the problem don’t continue to contribute “I have this problem too” posts.

Thanks

Apple has now released Safari 13.0.1 - which apparently fixes the issue. Hopefully one of these days Apple hires and/or properly funds a real QA department for their software.

Same issue here. I have tried safe mode, etc and nothing seems to fix it