Can't download attachments from gmail

I've finally found the problem, and it was in Google gmail, not in Safari. The fact that it started just after a Safari update was coincidental.

There's a feature in gmail called "labs" which give you various ways of handling email. Google troubleshooting suggested turning off all the labs if there was trouble downloading. (Interestingly, none of the labs had ever been enabled in my original copy of gmail because I never bothered to look at them.) In the new copy, with all of the labs disabled (just like the old copy), I can now download attachments.

Thank you for all your help and suggestions.

The download location was previously set to the Downloads folder on the Dock. I reset the location to the Desktop, but nothing changed--no downloads.

Usually, when I click on an attachment to download it, a round icon pops up and goes to the Downloads folder. Now, no icon, no download, no nothing.

The problem is not with Mail for Mac--it's in Safari, using gmail. I could download attachments by clicking on them before the latest security update for Safari; I cannot download them at all from gmail now.

I can save attachments to my Google drive from gmail and view them there. I can forward the emails to Mail for Mac or Yahoo and open them there, but I cannot open or download them from Safari with gmail, and this is a new problem since the Safari update.

I'm using Safari.

I made no changes to anything, other than to install the update, Safari 10.

General preferences are already set up like this and have been for several years.